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Institutionen för Systemteknik Systemteknik

Department of Electrical Engineering Examensarbete 

Upgrading and Performance Analysis of Thin Clients in Server Based Scientific Computing Master Thesis in ISY Communication System By Rizwan Azhar

LiTH-ISY-EX - - 11/4388 - - SE  Linköping 2011

Department of Electrical Engineering Linköpings universitet SE-581 83 Linköping,

Linköpings Tekniska Högskola Linköpings universitet Sweden 581 83 Linköping, Sweden  

 

Upgrading and Performance Analysis of ThinScientific Clients Computing in Server Based Master Thesis in ISY Communication System at Linköping Institute of Technology  By Rizwan Azhar

LiTH-ISY-EX - - 11/4388 - - SE 

Examiner: Dr. Lasse Alfredsson Advisor:

Dr. Alexandr Malusek

Supervisor:  Dr. Peter Lundberg 

 

 

Presentation Date

Department and Division

04-02-2011 Publishing Date (Electronic version) 

Department of Electrical Engineering

Language

Type of Publication

X English Other (specify below)

Licentiate thesis X Degree thesis Thesis C-level Thesis D-level Report Other (specify below)

55 Number of Pages

ISBN (Licentiate thesis) ISRN: LiTH-ISY-EX LiTH-ISY -EX - - 11/4388 - - SE 

Title of series (Licentiate thesis)

Series number/ISSN (Licentiate thesis) 

URL, Electronic Version  http://www.ep.liu.se   Publication Title

Upgrading and Performance Analysis of Thin Clients in Server Based Scientific Computing Author  Rizwan Azhar Abstract  Server Based Computing (SBC) technology allows applications to be deployed, managed, supported and executed on the server and not on the client; only the screen information is transmitted between the server and client. This architecture solves many fundamental fundamental problems with application deployment, technical support, data storage, hardware and software upgrades.

This thesis is targeted at upgrading and evaluating performance of thin clients in scientific Server Based Computing (SBC). Performance of Linux based SBC was assessed via methods of both quantitative and qualitative research. Quantitative method used benchmarks that measured typical-load performance with SAR and graphics performance with X11perf, Xbench and SPECviewperf. Structured interview, a qualitative research method, was was adopted in which the number of openended questions in specific order was presented to users in order to estimate user-perceived performance. The first performance identified the CPU speed. second bottleneck, with respect to graphics intensive applications,bottleneck includes the networkwas latency of the X11 The protocol andperformance the subsequent performance of old thin clients. An upgrade of both the computational server and thin clients was suggested. The evaluation after the upgrade involved performance analysis via quantitative and qualitative methods. The results showed that the new configuration had improved the performance. Keywords SBC, Performance analysis, Xbench, X11perf, SPECviewperf,

 

 

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The publishers will keep this document online on the Internet  –  or  or its possible replacement  –   for a period of 25 years starting from the date of publication barring exceptional circumstances. The online availability of the document implies permanent permission for anyone to read, to download, or to print out single copies for his/her own use and to use it unchanged for noncommercial research and educational purposes. Subsequent transfers of copyright cannot revoke this permission. All other uses of the document are conditional upon the consent of the copyright owner. The publisher has taken technical and administrative measures to assure authenticity, security and accessibility. According to intellectual property law the author has the right to be mentioned when his/her work is accessed as described above and to be protected against infringement. For additional information about Linköping University Electronic Press and its procedures for  publication and for assurance of document integrity, please refer to its www home page: http://www.ep.liu.se/.  http://www.ep.liu.se/.

© Rizwan Azhar  

 

 

Abstract Server Based Computing (SBC) technology allows applications to be deployed, managed, supported and executed on the server and not on the client; only the screen information is transmitted between the server and client. This architecture solves many fundamental  problems with application deployment, deployment, technical suppo support, rt, data storage, hardware and software software upgrades. This thesis is targeted at upgrading and evaluating performance of thin clients in scientific Server Based Computing (SBC). Performance of Linux based SBC was assessed via methods of both quantitative and qualitative research. Quantitative method used benchmarks that measured typical-load performance with SAR and graphics performance with X11perf, Xbench and SPECviewperf. SPECviewperf. Structured interview, a qualitative research research method, was adopted in which the number of open-ended questions in specific order was presented to users in order to estimate user-perceived performance. The first performance bottleneck identified was the CPU speed. The second performance  bottleneck, with respect respect to graphics intensive applications, applications, includes the network latency latency of the X11 protocol and the subsequent performance of old thin clients. An upgrade of both the computational server and thin clients was suggested. The evaluation after the upgrade involved performance analysis via quantitative and qualitative methods. The results showed that the new configuration had improved the  performance.

 

 

Acknowledgement In the beginning, unlimited thank to Almighty ALLAH, THE most Merciful and Beneficent, without Whom I would not be able to complete this thesis. I would like to thank my advisor Dr. Alexandr Malusek, for his guidance and magnificent technical support. Many thanks for his availability even on weekends and for his effort to make this thesis more interesting. In addition, I also want to thank Dr. Peter Lundberg for providing this opportunity in a very  professional and and competitive env environment. ironment. Also, I would like to thank my examiner Dr. Lasse Alfredsso Alfredsson, n, who explained to me the skills of technical writing. I also like to thank Mr. Shehryar Khan for proof reading of the thesis report. Last but not the least, tremendous gratitude to my parents for the support, love and prayers. I dedicate this thesis to my parents, especially the daily motivation that I have received via Skype, without which I would not be able to complete this thesis.

 

 

Acronyms API DDI

Application Programmable Interface Device Driver Interface

DNS DRI DXPC GDI GUI GNOME ICA IceWM IOSTAT IPC ISAG KDE  NFS  NIS  NTC-O  NTC-T OpenGL OTC-O RDP RFB SAR SBC SPEC SSH TCC TCP TLCOS

Domain Name System Direct Rendering Infrastructure Differential X Protocol Compressor Graphics Device Interface Graphical User Interface GNU Network Object Model Environment Independe Independent nt Computing Architecture Ice Window Manager Input Output Statistics Inter Process Communication Interactive System Activity Grapher K Desktop Environment Network File Sy System stem Network Information Se Service rvice New Thin Client with ooriginal riginal software New Thin Client with T ThinLinc hinLinc Software Open Graphics Library Old Thin Client with original software Remote Desktop Protocol Request Frame Buffer System Activity Report Server based Computing Standard Performance Evaluation Corporation Secure Shell Thin Client Computing Transport Communication Protocol ThinLinc Client Operating System

VNC VMSTAT XCB XDMCP

Virtual Network Computing Memory Statistics X Protocol C Languag Languagee Binding X Display Manager Control Protocol

 

 

Table of contents Chapter1: Introduction 1.1 Introduction…….…………………………………………………………………………..1  1.2 Aims………………………………………………………………………………………..2 1.3 Layout……………………………………………………………………………………...3 Chapter2: Background 2.1 Introduction..…………………………………………………………………………….....5 ....5 2.2 Advantages of SCB…………………………………………………………………...........6 .........6 Manageability……………………………………………………………......................6 ....................6 Security………………………………………………………………………...............7 ............7 Scalability……………………………………………………………………...............7 Availability……………………………………………………….................................7 Cost reduction.................................…………..................... ............................................ ..........................................7 ...................7 2.3 SBC Implementation…………… Implementation………………………………………………………………………. ………………………………………………………….7 2.3.1 Hardware Implementation………………………………………………………..7 Thin client..………………………………………………………………………7 ………………………………………………..................................7 Workstation 2.3.2 Software Implementation……………………………………………………….. .8 .8 RDP……………………………………………………………………...............8 ICA………………………………………………………………………………9  NX…………………………………………………………………….................9 ...............9 VNC…………………………………………………………………………….10 10 X Window system……………………………………………………...............11 X client libraries and extensions……………………...................12 Mesa3D………….……...........................................12 DRI…………………...............................................12 XSync………………...............................................12 XFT2……………………………............................12 XCB………………………………….....................12 ..................12 ThinLinc……………………………………………………………..................13 ...............13

Chapter3: Performance analysis tools and benchmarks 3.1 Introduction…………………………………………………… Introduction…………………………………………………………………………… ……………………….....15 3.2 Performance analysis tools…………………………………………………………….....15 ....15 IOSTAT………………………………………………………………………............15 ...........15 VMSTAT……………………………………………………………………..............16 SAR…………………………………………………………………………………...17 ISAG………………………………………………………………………………….18 SPEC CPU……………………………………………………………………............18 .........18 3.3 Graphics Benchmarks………………………………………………………………….....18 X11perf…………………………………………………………………............18 ...........18 Xbench………………………………………………………………………….18 SPECviewperf…………………………………………………….....................19

 

 

Chapter4: Typical-load performance analysis 4.1Introduction………………………………………………………..………………………21 Old computing environment……………………….…………………………...22  New computing computing environment………………….…….…………………............24 4.2 Methods…………………………………………………………………………………...24 ..24 4.3 Results………………………………………………………………………………….....24 CPU Utilization………………………………………………………………...25 .25 Paging statistics………………………………………………………………...26 26 IO transfer rate………………..………………………………………………...27 27 4.4 Discussion…………………………………………………………………………….......28 4.5 Conclusion………………………………………………………………………………..29 Chapter5: Graphics performance analysis 5.1 Introduction……………………………………………………………………………….31 5.2 Methods…………………………………………………………………………………...32 5.3 Results……………………………………………………………………………….........34 5.3.1Xbench…………………………………………….………………………34 Effect of desktop environment……....…..……………................37 Effect of remote display………………………………................38 5.3.2 X11perf…………………………………………………………………...39 .39 SPECviewperf………………………………………………………… ....42 5.4 Discussion5.3.3 …………………………………………………………………………... ........43 ........43 5.5 Conclusion………………………………………………………………………………..43 .43 Chapter6: User perceived performance analysis 6.1 Introduction……………………………………………………………………………….45 6.2 Methods...………………………………………………………………………………....45 6.3 Results…………………………………………………………………………………….46 User interviewing before upgrade.…...………………………………………...46 .46 User interviewing after upgrade.. u pgrade..……..…………………………..……............47 6.4 Discussion………………………………………………………………………………...47 6.5 Conclusion ……………………………………………………………………………….47 Chapter7: Conclusion 7.1 Conclusion………………………………………………………………………………..49 .49 Appendix A…………………………………………………………………………………...50 .50 Appendix B…………………………………………………………………………………...52 Appendix C…………………………………………………………………………………...53 .53

Bibliography…………………………………………………………………………………..55

 

 

List of Figures Figure1: Thin client computing model………………………………………………………....2 .2 Figure2: SBC Environment……………………………………………………………….........6 .......6 Figure3: RDP Architecture…………………………………………………………….............8 ...........8 Figure4: NX Architecture……………………………………………………………….........10 Figure5: VNC…………………………………………………………...……………….........10 Figure6: X Architecture………………………………………………………………............11 Figure7: IOSTAT command output……………………………………………………..........16 .......16 Figure8: VMSTAT command output…………………………………………………………16 Figure9: SAR command output……………………………………………………………....17 .17 Figure10: Schematic view of network configuration…………………………………………23 Figure11: CPU utilization graph on a) nestor and b) tintin…………………………………...25 Figure12: Paging statistics graph on a) nestor and b) tintin…………………………………..26 Figure13: IO transfer rate graph on a) nestor and b) tintin…………………………………...27 Figure14: Xbench performance on a) KDE b) Gnome and c) IceWM………………….........35 Figure15: Xbench performance ratio on a) KDE b) Gnome and c) IceWM………………….36 Figure16: Desktop environment performance on NTC- O……………………………………37 Figure17: Remote display performance………………………………………………………38 Figure18: X11perf performance on a) KDE b) Gnome and c) IceWM……………………....40 Figure19: X11perf performance ratio on a) KDE b) Gnome and c) IceWM…………………41 Figure20: SPECviewperf performance on nestor ,tintin and NTC-T.………………………..42

 

 

List of Tables Table1: IOSTAT parameters………………………………………………………………….16 16 Table2: VMSTAT parameters………………………………………………………………..16 16 Table3: Old Server and workstations configuration…………….…………………………....22 .22

Table4: Old Thin clients configuration……………………………………………………….22 22 Table5: New server configur ation……………………………………………………………. ation…………………………………………………………….24 24 Table6: New thin client configuration…………………………………………………..........24 .........24 Table7: SPECint results…….………………………………………………………………...28  Table8: SPECfp results......…………………………………………………………………...28  Table9: Experimental design for X11 and Xbench…………………………………………...32 .32 Table10: Experimental design for remot e display……………………………………………32 Table11: Desktop environment versions……………………………………………………...33 Table12: Experimental design for SPECviewperf……………………………………………33 Table13: Ratio of average performance of Desktop environment……………………………37 Table14: SPECviewperf results on Desktop environment……………………………………42 Table15: Performance evaluation based on user experience before upgrade…...……………46 Table16: Performance evaluation based on user experience after upgrade…...……………...47 Table17: Xbench tests………………………………………………………………………...51  Table18: Thin client technical t echnical specification comparison……………………………………..53  Table19: Considered alternatives for computational server...………………………………...53  Table20: Configuration alternatives for thin clients……………………………………..…...54 .54

 

 

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Introduction Concepts presented in this section come from an article by Yu et al [1].  Computing technology can be divided in to the three distinct phases of evolution: 1.  Mainframe Computing: Mainframe computing involves processing power to be condensed in a centralized system with all functionalities and resources. This type of architecture was popular during the 1960s up to the 1970s.   Drawbacks: Slow link speed, simple terminal and high cost-performance ratio. 2.  Standalone Computing: Standalone computing consisted of PCs and workstations  in

a client-server configuration through a PC LAN interface. These systems were equipped to handle a wide range of applications as more processing power and independent storage units were invested in the client. This reduced the load on the server which was used for additional file and print services. This type of architecture was popular during the 1980s. Drawbacks: Maintenance cost has increased, as applications were installed and executed on the client.   3.  Network-centric Computing:  Network centric computing is a decoupled client-

server configuration that enabled machines to access applications and data on the servers. This type of architecture was developed in the 1990s. Dominant form of a network centric computing is an Internet computing, which has changed the way applications were developed. Advantage: No applications have to be installed on the client. Disadvantages: Applications have to be reconfigured or redeveloped for the network architecture. 

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As applications have to be reconfigured for an Internet computing, the thin client computing models were developed to resolve the compatibility issues of data intensive applications with the widely popular internet computing architecture.

Client/Server Model 

Web-based Model

SBC Model

Figure 1: Thin client computing models

Figure 1 illustrates the Client server model, the Internet computing model and the Server Based Computing (SBC) model. The overall architecture of the three models is similar as all the application code is executed on the server side and the client devices are used to display screen updates. However the models use different protocols and data compression techniques for the communication between the client and the server. The models differ with respect to the functionality partitioning where the effort has been made to make the client layer thin. This impacts the networking protocol and data compression demands to reduce the network traffic and the client side processing. The SBC model is the thinnest model as it is only used to display screen updates. 1.2 Aims of this thesis Scientific calculations at the MR-unit were CPU intensive and required large amount of computer memory. Powerful computational servers were used for scientific calculations and Unix workstations were were used for data processing. Up to three students w worked orked in a sma small ll computer room at the MR-unit. Heat and noise produced by the workstations would have made working conditions in this t his room difficult. Therefore only monitors, keyboards and mice were placed in the computer room; the workstations were placed in a separate "machine" room and connected via long (about 18 m long) cables. This configuration worked well for Sun workstations with display resolutions up to 1280 x 1024 pixels. For higher resolutions, however, either very expensive DVI extenders or a solution based on thin clients were needed. The latter was implemented in 2007 using thin clients in an SBC configuration. This infrastructure worked well for several years. It became obsolete in 2010 as the server operating system was no longer supported by the manufacturer and the speed of the thin clients was not sufficient for new, graphics intensive applications. An update of the IT infrastructure was needed.

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The purpose and scope of this thesis is to (i) analyze the current computer configuration at the MR-unit of the Department of Radiological Science (ii) propose an upgrade (iii) implement the proposed changes and (iv) analyze the new computer configuration at the t he MR-unit. 1.3 Layout This section defines the layout and a brief introduction of the thesis. Chapter1: Introduction This chapter describes the evolution phases of computing technology, the thin client computing models, and aims of the thesis. Chapter 2: Background This chapter introduces the SBC, its advantages, components and various protocols based on SBC. Chapter 3: Performance analysis tools and benchmarks This chapter defines the performance analysis in general, tools and benchmarks used for the  performance analysis analysis of the SBC en environment. vironment. Chapter 4: Typical-load performance analysis This chapter briefly presents the load performance analysis, the methods and the results, discussion and conclusion. Chapter 5: Graphics performance analysis This chapter describes the graphics performance analysis of the implemented SBC, the methods and the results, discussion and conclusion. Chapter 6: User perceived performance analysis This chapter presents the results and discussion on the performance analysis based on user experience via qualitative research method. Chapter 7: Conclusion This chapter describes the summary of the thesis work.

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2

Background

 

2.1 Introduction Concepts described in sections 2.1 and 2.2 are based on information provided in [2].   Server based computing (SBC)onisthe a server technology whereby are screen deployed, managed, supported and executed and not on the applications client. Only the information is transmitted between the server and the client. SBC is also known as Thin Client Computing (TCC) and typically consist of the three components: a terminal server, one or more thin clients, and a communication protocol. The terminal server runs an operating system that supports a multi user environment. The thin client runs a stripped-down version of an operating system that is capable of running a  program that connects the thin client to the server. The last component is the protocol which allows the communication between thin clients and the t he terminal server by b y sending keystrokes, mouse clicks and screen updates via network. In larger deployments, more than one terminal server may be used; load balancing software then distributes workload across the servers.

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Figure 2: Server based computing environment 

SBC implements a centralized computing model, in which users share software and hardware resources of the dedicated servers via thin clients. In this way SBC minimizes administration costs and also increases the utilization of resources, some advantages of SBC are discussed in section 2.2. 2.2 Advantages of SCB Advantages of server based computing are manageability, security, availability, scalability and cost reduction which are discussed in this section. Manageability

An SBC environment implements a centralized model which theondata deployment and the management is more convenient computing as most of the work in is performed the servers only. 6

 

Security

In SBC, all the data is kept on secure servers. Data security is covered from the perspectives of both the physical security and the technical security. The physical security in the sense that server normally resides in a server room, in which only authorized persons are allowed to enter. The technical security is provided by the use of protocols to keep the data integrity and confidentiality. Scalability

In an SBC environment, new thin clients can be added to the system to support more users without changing the architectural design of the system. Similarly new servers can be added to balance the load of the system without changing the architecture of the th e system. Availability

Servers can support fault tolerance. For instance features like redundant disk drives, redundant power supplies etc. Moreover they can run special applications to manage the load and monitor the performance. In case of a server failure, the user is redirected to a different server. Cost Reduction

Server based computing reduces costs on account of hardware, software, maintenance, administrator staffing and training etc. 2.3 SBC Implementation There are two aspects of an SBC implementation: SBC Hardware implementation and SBC Software implementation. 2.3.1 SBC Hardware Implementation

There are two ways of SBC hardware implementation namely (i) thin client and (ii) workstation or personal computer (PC). Thin Client

A thin client is a computing device which totally relies on a server for computing. All application logic logic is executed oonn the server. A thin client comprises of a display screen, a mouse and a keyboard combine with the adequate processing capabilities and memory for tthe he graphical rendering rendering and the network co communication mmunication with a serv server. er. It has no long-term uuser ser state and requires no disk. Workstation

An ordinary workstation or Personal Computer (PC) can also be used for an SBC. The workstation has to be installed with an SBC supportive operating system like the TLCOS [27]. Alternatively, if a full OS is not feasible at the workstation then a client side application 7

 

of the SBC supporting software being used at the server, has to be installed on the workstation. 2.3.2 SBC Software Implementation

The most important component of the SBC is a software protocol which is used to facilitate the communication between a thin client and a server. There are several protocols for SBC some of them are discussed in this section. RDP

Remote Desktop Protocol (RDP) is a protocol developed by Microsoft which provides remote access services.At the server side, RDP utilizes a virtual display driver to render the display information. After creating the local display information, this information is pushed in network packets with the help of RDP protocol and then forwarded across the network to the client side. At the client side, RDP receives the packet via network and transforms these network packets into appropriate Graphics Device Interface (GDI) Application Programmable Interface (API) calls. In this way, GUI is displayed on the client side. Upon displaying the GUI the user response is activated on the input path. User responses consisting of mouse clicks and keyboard events are then forwarded to the server. On the server side, RDP ttakes akes an advantage of its own keyboard and mouse driver to collect the screen updates. RDP uses sixty four thousand virtual channels for the data communication with multipoint transmission [28]. Key strokes, Mouse ops

Cache

Bitmaps, Colour tables, Ordering ops, Drawing Ops, etc

Server 

Client Figure 3: RDP Architecture

Performance of the RDP is affected by display encoding, encoding compression, display update policy and client caching. For the display encoding, RDP uses graphics primitives just like Windows DDI video driver interface. The encoding mechanism uses higher-level semantics and potentially differentiates between various graphic primitives including boxes, glyphs, fills etc. The higher-level semantics saves bandwidth but requires an additional  processing at the client side. RDP uses the combination of run-length encoding and other compression schemes for the compression of display encoding. For the display update policy,  buffers are used at the server side. On the client side, contents are flushed at a varying rate which depends on the input from the client side and the graphical output produced at the server side. RDP also uses client side caching to accelerate the display of graphical objects. RDP 4.0 and 5.0 clients uses 1.5 MB of RAM for graphical objects including glyphs, bitmaps etc. RDP 5.0 also uses 10 MB persistent disk cache for caching just like paging system [5].

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The RDP uses RC4 encryption algorithm to secure the data communication which provides three different levels of security namely low, medium and high. The RC4 low level security  provides unidirectional encryption with the help of a 56 or 40 bit key encryption. RC4 medium level security uses bidirectional encryption with the same key length used in low level security. RC4 uses high level security and provides bidirectional encryption with 128 bit key encryption [6]. ICA

Independent Computing Architecture (ICA) is a protocol developed by Citrix to provide remote access service. On the server side, ICA uses a local device driver to render graphics. For encoding the graphical information, it uses a graphic primitive which is similar to a Windows video driver interface and RDP. The encoded ICA packet is then compressed with a combination of run length coding and other compression techniques. The TCP protocol encapsulates encapsula tes the compressed ICA packet and forwards iitt to the network layer, for creating the session between the client and the server side. On the client side, the ICA client software intercepts the server message via the TCP protocol and fetches the screen from the server. As a result, the session is created and the ICA client software in return sends the screen updates to the server. On the server side, ICA uses a screen update policy with the help of buffers. The contents of the buffer flushed with changing rate according to the user input in the form of key strokes, mouse events and the amount of display output being generated. To observe  buffered display an for evaluator Speed-screen used. the The clientdata side, it uses a queuing mechanism sendingnamed and receiving updatesisform theOn server. transmission rate can be changed in the client software. The ICA client uses a caching mechanism before downloading updates from the server, which increases the transport performance. The cache is first checked for updated information and if the update is true it downloads from cache instead of downloading from server, across the network [5]. Just like RDP, the ICA performance also depends on display encoding, encoding compression, display update policy and client caching. The display encoding, encoding compression and display update policy characteristics are similar to RDP. However, for client caching, ICA uses 3.0 MB of RAM for graphical objects and it also uses a disk for persistent caching [5]. NX

G.F Pinzari of NoMachine originally developed an NX which uses the SSH protocol to securely connect and display the remote access services. The NX was derived from the Differential X Protocol Compressor (DXPC). It uses a two way proxy system to provide the data communication between the local system and the remote system with the help of the NX  protocol based on the X window system. The remote proxy communicates with the remote X11 applications and uses the X11 protocol. The remote proxy incorporates a kind of X server, named nxagent, that becomes the X server of all the remote X clients. The nxagent translates the X11 protocol into the NX protocol, receiving X11 requests as drawing commands and sending them to the local proxy. Thus the remote NX proxy poses itself to the X clients as if it is the X server. All the roundtrips take place at this point and since they happen on the same host machine, they are quickly resolved through the UNIX domain sockets. The local NX proxy communicates with the local X server and interprets the NX  protocol back to X11.  Both the local and the remote proxy keep their own cache of 9

 

transferred data. These two sets of cache are synchronized to be useful for saving all transmission of pixmaps, icons etc between the local and the remote proxies [9].

Figure 4: NX Architecture 

 NX also has a potential to run over slow network connections with the help of compression mechanism which reduces the round trip time and increases the drawing speed of the X window system. When NX receives a new X request, it evaluates the checksum and tries to find the request in the message-store. The Message-store is a cache for holding the lasts X messages sent to the main memory. After searching, if the message exists in the message store, the NX sends the status s tatus information combined with the position information of message store and disparity encoding of all the fields except the checksum. In this way NX achieves the compression boost [9]. VNC

Virtual Networking Computing (VNC) is used to provide the remote desktop sharing with the help of Request Frame Buffer (RFB) protocol. It mainly comprises of the three components: a VNC viewer, a VNC server and a RFB protocol. A VNC viewer resides on the user side which transmits the keyboard strokes and the mouse events on a network. The VNC server sends a remote display as the rectangular bitmap images to the VNC viewer. VNC uses different encoding methods to control the bandwidth utilization. The most undemanding method is a raw encoding, in which the VNC server sends the data in left-to-right scanline arrangement, untilon thethe full-screen of the display, andencoding after thatscheme only transfer those  pixels that varies keyboardtransmission and the mouse events. This is effective for a small portion of screen changes on every updates and suffers a lot for large variation in screen positions. RFB protocol works with the TCP protocol on port 5900+N; where N is the number which is used for every remote display attached. The protocol is platform independent, as it runs on frame-buffer level, which allows it to executing on different operating systems for example Unix, Linux, MAC and Windows.

Figure 5: VNC

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X Window System

The X window system is a network-transparent window system, which was developed at the MIT in 1984. It provides a Graphical User Interface (GUI) for both the local users as well as the network based users. The X window system is based on the client server model. The reference view in an X window system is the application and not the t he end user and this change in reference causes an inversion of the client server model with respect to the traditional sense. The user's terminal now acts as the server and the application acts as the client, as applications are now end users of services therefore behave as the clients. There are two scenarios; if the client and the server reside on the same system they interact with the Inter Process Communication (IPC) but if the client and the server reside on the different system a network connection is used. Simultaneous multiple connections are supported for two cases, a single client can open several connections to a server and several clients can open several connections to various servers at the same time. The X-server manages the display and the clients; it multiplexes requests from the clients to the display and supports the reverse by de-multiplexing the keyboard and the mouse inputs back to the appropriate clients. Typically, the server is implemented as a single sequential process, using round robin scheduling among the clients [10].

Figure 6: X windows architecture 

The X server communicates with different X client programs by calling Xlib. The Xlib is an X window system protocol client library written in the C programming language. The Xlib forwards a request from the client to the server by accumulating the request in a buffer known as the Request buffer. The buffer is flushed when all the requests are forwarded to the server. The Xlib not only stores the send requests in a buffer but also accumulates received events in a queue. This queue is used by the client application to examine and retrieve events. The client application may also flush the request buffer incase of the queue blocking [11]. 11

 

X Client Libraries and Extensions

The X window system consists of various libraries and extensions. Libraries and extensions related to graphics performance are discussed in this section. MESA3D 

Mesa is an opencan source implementation of in OpenGL for rendering 3D graphics. The rendering be performed purely the software but if the theinteractive graphic card supports hardware acceleration of 3D graphics then the Mesa can utilize these functions too [14]. DRI 

DRI is an acronym for Direct Rendering Infrastructure, which enables the hardware acceleration by accessing video hardware without requiring data to be passed through the X server [29]. XSYNC 

X Synchronization is an extension which provides primitives that allows the synchronization  between the clients to take place entirely within the X server [[30]. 30]. This extension eliminates network errors and provides the real time synchronization for the multimedia applications. XFT2 

Xft2 is a freetype2 library which is used for rendering fonts. It uses render extension for the accelerated text drawing. However if the render extensions are not available then it uses the core protocol to draw the client-side glyphs [14]. XCB 

XCB is the C language library for an X window system. It is an alternative to Xlib, designed to solve the issues of the Xlib by providing latency hiding, threaded applications com compatibility patibility and small platform compatibility. The latency hiding issue is solved by redesigning the network layerisprotocol from synchronous asynchronous small the platform compatibility solved by having an XCB toasan a binding insteadinterface. of trying The to reduce large Xlib code. The XCB is designed keeping threaded applications in mind; Xlib API was error prone. In addition, the XCB provides a basis for toolkit implementation, direct protocol-level  programming, and lightweight emulation of commonly used portions of the Xlib API. Toolkits provide user interface elements, examples examples are GTK+, Qt, Motif, Intrinsics, etc [13]. GTK+ is a rich toolkit in features, which is initially designed for the GUI of X window system. The toolkit is written in C language which supports various languages like Python, C++, etc. It uses an Xlib to display graphics on the screen. GTK+ implementation comprises of the three libraries Glib, Pango and ATK. Glib provides a low level portability layer and common functions which is used by GTK+ and Gnome, the Pango provides an internationalized text layout and the ATK deals with the accessibility. Versions of GTK+ are available as GTK+1.1, GTK+1.2, GTK+2.0, etc and the latest stable release is GTK+ 2.20 [12]. 12

 

Qt is a toolkit for creating the GUI and the Non-GUI programs. The toolkit is widely used  because it supports many platforms (X11, Windows, Mac OS X etc) and has APIs that are tailored for tasks such as file handling, process handling threading etc. The toolkit is written in C++ and also supports many different languages with the help of language bindings. Qt also provides an internationalized text and the unicode support. Versions of Qt are available as Qt1, Qt2 etc and the latest Qt4 has most accessibility support support [12]. The X protocol does not use any compression mechanism for the transport of the graphical objects on the remote display. The important factor in the performance of X protocol is a transport latency which depends on the round trip time; from the X-server to the X-client and  back to the X-server. The Xlib increases the transport latency as it mostly uses the synchronous operation; however, the design of XCB reduces the latency by introducing the asynchronous asynchrono us interface in the X protocol 14]. ThinLinc

ThinLinc is a software based implementation of an SBC, developed by Cendio AB. Thinlinc not only enhances the mechanism of an SBC but also provide various add-ons which include encryption, single sign-on, clustering, smartcard support, and integrates different systems and services [26]. On servertoside is client generated with the localdesktop video device which transfers it on the the network the graphic ThinLinc by the graphical sharingdriver system known as Virtual  Network Computing (VNC). VNC uses the Request Frame Buffer (RFB) protocol which transmits mouse clicks, keyboard events and graphics updates from the VNC server to the VNC viewer. Thinlinc provides both the software and the hardware acceleration for 3D graphics. Software based acceleration acceleration is provided by the rapid integration of the OpenGL with the 3D graphic library Mesa. Hardware based acceleration is provided with the combination of TightVNC and the virtualGL. vir tualGL. TightVNC is a slightly modified version of VNC which uses Junior Picture Expert Group (JPEG) codec for the tight encoding; which gives intense graphics performance and extends streaming video encoding in the real time. VirtualGL allows remote access applications like tightVNC to execute the OpenGL commands with the full 3D hardware acceleration. Rendering of 3D data is performed on the application server with the 3D graphics accelerator. The rendered 3D images are sent on the network to the user side with the help of the TightVNC. A user use thinlinc-client to log on to the thinlinc server; in this process the thinlinc-client creates a secure shell (SSH) tunnel to the thinlinc-server. The client then attempts to authenticate with the VNC session manager known as VSM server. If the authentication succeeds, the client then again creates a SSH tunnel to the VSM agent. After the connection establishment with the VSM agent the tunnel for VNC viewer is then created to start the VNC viewer [26].

13

 

14

 

3

Performance analysis tools and benchmarks

 

3.1 Introduction Performance analysis is the process of evaluating and measuring the software/hardware  behaviour, with the help of information gathered, when the specific program/hardware operates. Performance analysis not only and predicts the future requirements of theevaluates system. the performance metric, but also indicates 3.2 Performance analysis tool There are various tools and techniques to analyze the performance of Linux based SBC. Some of the tools are discussed in this section. IOSTAT

IOSTAT acronym means Input Output Statistics. IOSTAT is used to monitor the system  performance with respect to the CPU and the disk uti utilization. lization. The tool records the number of  blocks read and written per second to each disk connected to the given system. It also calculates the time spent by the system in user, system, idle, steal, iowait, and nice mode [17]; see figure 7 and table 1. 15

 

[email protected]:/> iostat Linux 2.6.31.5-0.1-de 2.6.31.5-0.1-default fault (tintin) 09/13/10 _x86_64_ (8 CPU) avg-cpu: %user %nice %system %iowait %steal %idle 3.40 0.19 0.91 0.16 0.00 95.34 Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn sda 1.00 7.03 21.52 25166094 77090737 sdb 0.23 4.35 78.12 15588060 279827257 scd0 0.00 0.26 0.00 936216 0 Figure 7: IOSTAT command output Table 1: Quantities reported by IOSTAT.

%user %nice CPU

%system %iowait %steal %idle

Disk I/O

Tps  blk_read/s  blk_wrtn/s  blk_read  blk_wrtn

Percentage of CPU utilization that occurred while executing at the user level. Percentage of CPU utilization that occurred while executing at the user level with nice priorities. Percentage of CPU utilization that occurred while executing at the kernel level. Percentage of time that CPU was idle during which the system had an outstanding disk I/O request. Percentage of time spent in involuntary wait by the virtual CPU while the hypervisor serves another virtual processor Percentage of time spent by CPU in which do not have any process to execute Input/Output transfers per second to the device Number of block blockss read from the device device per secon secondd Number of block blockss written to the device per second total number of bloc blocks ks read from the device total number of bloc blocks ks written to the dev device ice

VMSTAT

VMSTAT acronym means Virtual Memory Statistics. VMSTAT is used to determine the resource with respect to processes, virtual memory, paging the activity, diskutilization transfers and CPU utilization activity. The tool uses kernel tables and counters to evaluate resource with the help of files like /proc/meminfo, /proc/stat, /proc/*/stat and then presents the result [18], see figure 8 and table 2 for more information. [email protected]:/> vmstat  procs -----------memory---------- ---swap-- -----io---- -system-- -----cpu-----r b swpd free buff cache si so bi bo in cs us sy id wa st 0 2 60124 525984 258968 38071688 0 0 1 6 0 1 4 1 95 0 0 Figure 8: VMSTAT command output

16

 

Table 2: Quantities reported by VMSTAT

R Process B Swpd Free Memory Buff Cache Paging IO System CPU

Si So Bi Bo In Cs Us Sy Id Wa St

Number of processes waiting for run time Number of processes in uninterruptable sleep Virtual memory used (in kibibytes) Virtual memory idle (in kibibytes) Memory (in kibibytes) used for buffering Memory (in kibibytes) used for caching Amount of memory memory swapped swapped to in disk from(per disksecond) (per second) Amount of Blocks (per second) receive from block device Blocks (per second) send to block device Total number of interrupts (per seconds) including clock Total number of context switches (per second) Percentage of CPU utilization that occurred while executing at the user level Percentage of CPU utilization that occurred while executing at the kernel level. Percentage of time spent by CPU in which do not have any process to execute Percentage of time that CPU was idle during which the system had an outstandingof disk I/Ospent request. Percentage time in involuntary wait by the virtual CPU while the hypervisor serves another virtual processor

SAR

SAR acronym means System Activity Report. SAR collects data reports and records the system activity information. The activity information includes CPU utilization, IO statistics, memory statistics, paging statistics, system statistics, network statistics etc. For data collection, the system activity data collector (sadc) command is used which samples data from f rom kernel tables and counters. The sa2 command is used to write a daily report activity generated from the sadc. As a result, the tool monitors major system resources see figure 9 for more information. The tool writes to a standard output, the contents of selected cumulative activity counters in the operating system. The accounting system, based on the values in the count and interval  parameters, writes information in the specified number of times spaced at the specified intervals in seconds [19]. [email protected]:~> sar -u 2 5 Linux 2.6.31.5-0.1-de 2.6.31.5-0.1-default fault (tintin) 11/09/2010 _x86_64_ (8 CPU) 03:32:45 PM CPU %user %nice %system %iowait %steal %idle 03:32:47 PM all 0.92 0.00 0.41 0.00 0.00 98.67 03:32:49 PM all 0.06 0.00 0.22 0.00 0.00 99.72 03:32:51 PM all 0.09 0.03 0.09 0.06 0.00 99.72 03:32:53 PM all 0.06 0.00 0.13 0.00 0.00 99.81 03:32:55 PM all 0.06 0.00 0.28 0.06 0.00 99.60 Average:

all 0.24 0.01 Figure 9: SAR command output

0.23 17

0.03

0.00

99.51

 

ISAG

ISAG acronym means Interactive System Grapher. ISAG does not evaluate the performance, however, it helps in the performance analysis, because ISAG displays the system activity information graphically. The data being generated from SAR are transformed in to tabular form and the tabular form is then plotted with the gnuplot [20]. SPEC CPU

The SPEC CPU is designed to provide performance measurements that can be used to compare the computing intensive workloads on different servers [25]. It includes two  benchmark sets namely CINT and CFP. The CINT benchmark is used for measuring and comparing computing intensive integer performance, The CFP measures floating point  performance. 3.3 Graphic benchmarks There are various graphic benchmarks for the Linux based SBC. Some of the graphic  benchmarks are are discussed in this ssection. ection. X11perf

The X11perf is a graphic benchmark, which is used to analyze the performance of the X server. The benchmark executes various performance tests on the X server and reports the  performance for executed tests. X11perf is a comprehensive benchmark which performs 384 tests to calculate the performance, for instance drawing of lines, circles, rectangles, copy plane, scrolling, stipples, tiles etc. The benchmark not only measures the traditional graphic  performance, but also measures the window managemen managementt performance. X11perf tests measures the time to initialize an application, mapping of windows from already existence window to new windows, reorganizing the windows in different positions, mapping of  bitmaps in to pixels etc. etc. In addition, it also eexplores xplores the pa particular rticular strengths and weaknesse weaknessess of servers, to analyze and improve a server performance. X11perf benchmark when executed, it firstly calculates the round trip time to the server, and parts this out of the final timing reported. It makes sure that the server has really executed the task requested by fetching a  pixel back from the test window [21]. X11perfcomp is a utility of X11perf which helps in the graphics performance analysis, as it compares the different X11perf result files and represents the result in a tabular form. As a result, the X11perfcomp is used to compare the performance of different platforms. X-bench

X-bench is a graphical benchmark which is used to analyze the performance of the X server. To analyze the performance it executes 40 tests which include drawing of lines, circles, windows etc on the X server. The X-benchmark measures the performance by calculating the time it takes to complete each and every individual test on the X server. Each test sends the instructions with awaiting known time interval normally ten seconds. Xbench remain silent till the server executed the given instruction with the help of XSync, then the server interacts with a graphic-controller using another instruction via fifo/pipe/buffer. In the end, Xbench examines back part of the screen. Examining back part of the screen assures that each pixel is 18

 

displayed on the X server and does not reside in the instruction queue of server. The Xbench execute tests in three levels which can be set via command line interface, however, if no level is defined the default level is used. Each test executes three times and the best evaluation is taken. As a result, it remo removes ves or reduce reducess the effects of daemons or oother ther backgroun backgroundd  processes [22]. SPECviewperf

The SPECviewperf is a benchmark developed by the Standard Performance Evaluation Corporation (SPEC) that evaluates an OpenGL graphic performance. It is a software program written in C language which is used to evaluate system performance in higher-quality graphics modes and also measure the scalability of graphics subsystems while running multithreaded graphics content. SPECviewperf performs various tests and measures the  performance in frames per second. It renders the data set in the predefined frame numbers, with animation between the frames displayed on the output screen. The benchmark use viewset to characterize the graphics representation of an application. Viewset comprises of tests, data sets and weights which are grouped with independent software vendors (ISV) that  provide weight-age for each test through which performance is reported in the output. Viewset include cataia, ensight, maya, pro, maya, solid works, ugx-nx, 3ds-max. For Detailed viewset description see [23]; however we have only discussed Ensight, Maya and Proe viewset. Ensight is a viewset which is used to evaluate display list and immediate mode paths with the help of OpenGL API. Maya viewset uses a blend of the immediate mode and the OpenGL to transfer the data through an OpenGL API. Proe viewset uses two models and three rendering modes for evaluating the graphics. It also uses gradient background for the efficient modeling of workload [23]. SPECviewperf measures the performance for the following entities:   3D primitives, including points, lines, line_strip, line_loop, triangles,



       

   

triangle_strip, triangle_fan, quads and polygons Attributes per vertex, per primitive and per frame Lighting Texture mapping Alpha blending

Fogging    Anti-aliasing   Depth buffering

  

Alpha blending is used for combining a transparent foreground color with a background color, as a result creates a new blended color. Fogging is a process which is used to improve the acuity of distance. Anti-aliasing refers to a process that reduces the appearance of aliased or  jagged edges, edges, produced due to fixed resolution ooff the computer disp display. lay.

19

 

20

 

4

Typical-load performance analysis 4.1 Introduction Performance of a load is described in chapter 3; the main ideas canbehavior be summarized as follows: Loadanalysis measurement refers to the practice of assessing a system’s under the load. The Load measurement may be performed during design, development, integration, and quality assurance phase. Performance analysis of a load evaluates the functional and  performance problems of a system under the load. Performance problems include those scenarios in which the system experience low throughput or long response time. Functional  problems include bugs in the system and deadlocks situations. Load is applied on the system with the help of the programs or the applications which utilizes system resources. The load of the system is measured by means of logs lo gs and reports generated by the monitoring application, which is already installed in the system. The monitoring application uses operating system kernel tables and counters to calculate the system resource usage information which includes CPU utilization, memory consumption, Disk I/O requests, paging activity etc. This chapter describes the old and new computer system configurations at MR unit and  performance analysis analysis of typical load in these two config configurations. urations. 21

 

Old computer environment at the MR-unit

The computer environment at the MR-unit consisted of servers, workstations and thin clients, see tables 3 and 4 and figure 10. Nestor and milou were computational servers, anka was a file server, abdallah and tchang were workstations. Three thin clients were connected to nestor via a private network; they were not assigned any DNS names. Table 3: Servers and workstations at the MR-unit (old computer environment)

Host name

Architecture Architecture

CPU

RAM

Operating System

milou

64 bit

2 x Opteron 1.8 4 GiB GHz

openSUSE 10.3

abdallah

64 bit

Pentium D 2.8 1 GiB GHz

openSUSE 10.3

32 bit

Intel Pentium 4 1 GiB 2 GHz

openSUSE 10.3

64 bit

Quad core Xeon 32 GiB 5150 2.66 GHz

openSUSE 10.3

tchang nestor

Table 4: Old thin clients at the MR-unit

Machine

CPU

RAM

CPU cache

Network

IGEL-2110

Via Eden 400

236 MiB

128 KiB

Ethernet,

LX Smart

MHz

100 Mbps

22

 

Figure 10: Schematic view of the network configuration at the MR-unit

 Nestor was the main computational server at the MR-unit. It was w as used to run applications like  jMRUI, Spm8, Idl, Analyze, Lcmodel, Sage, and Matlab. Thin client users used the XDMCP  protocol to connect to the nestor. Workstation users used SSH to run commands remotely on nestor. Milou had been the main main computational server at the MR-unit before 20 2007. 07. In the beginning of 2007, it was replaced in this role by the nestor. Since then it was used as a secondary computational server. Thin clients were connected to the Gigabit Ethernet switch, see figure 10. A remote session via the XDMCP protocol was automatically opened on the nestor when the thin client was turned on. Anka provided file services at CMIV and the MR-unit; nestor, milou, tchang and abdallah mounted user home directories via NFS version 3. It also provided the database database of unix users via the NIS service. Hostnames were resolved via DNS; the master and slave servers at the MR-unit were nestor and milou, mi lou, respectively.

23

 

New computer environment at MR unit

In the new computer environment the computational server nestor was replaced with tintin, see table 5. The new server was selected as the fastest serve server-class r-class machine that fitted in to the limited budget see table 19 in Appendix C for considered alternatives. alternatives. Table 5: New server configuration configuration at the MR-un MR-unit it

Host name

Architecture Architecture

CPU

RAM

Operating System

tintin

64 bit

2 x Intel Xeon Quad core E5560 2.8 GHz

48 GiB

openSUSE 11.2

The new thin clients were selected according to a recommendation by Peter Ästrand from Cendio AB, for having good price-performance ratio and software support from the manufacturer; see table 20 in Appendix C for available models and table 6 for the parameters of the chosen system. Table 6: New thin client at at the MR-unit 

Machine

CPU

RAM

CPU cache

Network

Fujitsu S550

AMD Sempron 200U, 1 GHz

1 GiB

256 KiB

Ethernet, 1 Gbps

4.2 Methods  To evaluate the performance of a typical load, SAR was used. The ISAG utility was used to display the data graphically. To create a typical load on both the servers, a MATLAB script was used. The script comprised of numerous calculations based on Magnetic Resonance Imaging (MRI) of brain and different parts of the human body. The load tests were executed on the nestor and the tintin during a weekend to eliminate the users’ influence on the system load. 4.3 Results Results generated by SAR and visualized by ISAG are presented in this section.

24

 

CPU Utilization

Figure 11a shows the CPU utilization during the load test. The process was started at 16.30 and took 2.12 hours to execute. The utilization of 35% indicates that the one CPU core was fully loaded while another one was loaded up to 50% only. We theorize this was caused by the inner working of how Matlab executed the script. The script put a low demand on network and disk resources. Therefore the task was mainly CPU intensive. Similar results were obtained for tintin, see figure 11b. The test started at 18:30 and took 1.32 hours to execute. The process fully utilized one core and 18% of another core. The speed up  1.6. in total run time was 2.121.32  1.6.

(a)

(b)

Figure 11: CPU utilization as a function of time for server nestor (a) and server tintin (b).

25

 

PAGING STATISTICS

Figure 12a shows paging and fault statistics obtain during the load test on nestor. The amount of paging and major faults was negligible. The rate of minor faults reflected the activity of a data processing job. For tintin, the rate of minor faults was substantly lower compared to the nestor, see figure 12b. Thetest. physical memory size was sufficient to meet the dynamic memory requirements of the load

(a)

(b)

Figure 12: Paging activity as a function of time for server nestor (a) and server tintin (b).

26

 

I/O Transfer Rate

Figure 13a shows shows the Input Output transfer rate during the load test on nestor. Substantly low disk IO requests were reflected. On the average, the network IO requests transmitted and received per second during the load test were 208.03 and 150 Kbps. For tintin, the similar results were obtained, see figure 13b. The disk IO requests were slightly reduced during compared thetest nestor. average networkKbps. IO request transmitted and received per seconds the to load wereThe 313.15 and 271.21

(a)

(b)

operations as a function of time for server nestor (a) tintin (b). Figure 13:  Number of IO operations 27

 

4.4 Discussion The overall throughput of the new system was higher compared to the old system for the following reasons: (i) individual cores of the new system were faster than cores of the old system. (ii) The new system had 8 cores while the old one had only four cores. The load test showed that tintin was 1.6 times faster than nestor. This result did not match with the standard testtheresult of and SPEC-CPU 2006performance, because thehowever, SPECcinttheand SPECfp  benchmarks evaluates integer floating-point Matlab load test was the combination of integer and floating-point. Some benchmark results were closer to the result which includes hmmer, xalancbmk, gcc in SPECcint and tonto benchmark in SPECfp, see table 7 and 8 for SPECcint and SPECfb benchmarks result respectively. Table 7: Ratio of SPECcint benchmark results on nestor and tintin

SPECcint benchmarks

Performance  P t int in  P nestor 

Perlbench

1.26

 bzip2 Gcc Mcf Gobmk Hmmer Sjeng Libquantum h264ref Omnetpp Astar Xalancbmk

1.25 1.54 2.40 1.24 1.57 1.52 12.11 1.25 1.77 1.35 1.55

Table 8: Ratio of SPECfp benchmark results on nestor and tintin

SPECfp benchmark benchmarkss

Performance  P t int in  P nestor 

Bwaves Games Milc Zeusmp Gromacs Cactusadm leslie3d  Namd

4.37 1.29 3.44 2.12 1.40 9.26 2.45 1.34

Dealii Soplex

1.38 2.34 28

 

 

 

Povray Calculix Gemsfdtf Tonto Ibm Wrf sphinx3

1.54 1.94 3.90 1.73 3.68 2.42 2.23

4.5 CONCLUSION The results showed that the load test was mainly CPU intensive. The range of load at the MR unit is very wide. Some applications are purely CPU intensive and some of them only perform mathematical operations on large number of files. The results generated from SAR and visualized by ISAG indicated that the new computer system of the MR unit is 1.6 times faster than the old one.

29

 

30

 

5

Graphic performance analysis 5.1 Introduction Graphics performance may affect the overall performance of applications. This aspect is especially important in the server based computing, because the speed of the server, thin clients, network has to be properly balanced. One way of measuring the overall graphics  performance is the usage usage of benchmark progra programs, ms, which evaluate the performance of both the hardware and the software implementations of visualization routines. It is well known that desktop environment may play a significant role in the graphical  performance; the more visually rich the eenvironment nvironment is the slow slower er the response ooff applications may be. On Linux, typically used desktop environments are KDE and Gnome. The X window system, however, does not require the usage of a full desktop environment; a full featured window manager like IceWM may be used instead. To keep the discussion in this chapter simple, we use the term “desktop environment” for IceWM also. List of all tested desktop environments is in table 11.

31

 

5.2 Methods Graphics performance was evaluated using graphics benchmarks X11perf, Xbench and SPECviewperf, refer to chapter 3 for more information about the benchmarks. Xbench and X11perf simulations were executed from KDE, Gnome and IceWM on the old thin client with the original software (OTC-O), new thin client with the original software (NTC-O), thin client with thethe Thinlinc the computational nestor and tintin. new In the case of Xbench, AWK (NTC-T), programming language was servers used to were process the output files. For X11perf, the X11perfcomp was used to merge the output data in a tabular form. Additionally, an R script (see appendix A and B) was written to visualize the data. Table 9: Experimental design for benchmark tests with Xbench and X11perf. Values in the

table give the number of repetition for each test. Desktop Environment

Xbench

X11perf

OTC-O

NTC-O

NTC-T

OTC-O

NTC-O

NTC-T

KDE

3

3

3

2

2

2

Gnome

3

3

3

2

2

2

IceWM

3

3

3

2

2

2

To estimate the effect of remote display i.e how the network transfer slows down the graphics device performance, the Xbench benchmark was also used in the configuration described in table 10. Table 10: Experimental design for the estimation of remote display. Values in the table t able give

the number of repetition for the Xbench test. X server/ Display device

Server

 Nestor

32

Tintin

Nestor

2

2

 

Table 11: Desktop environments at MR unit.

Server

KDE version

Gnome version

IceWM version

Tintin

4.3

2.28

1.12

 Nestor

4.0

2.20

1.00

SPECviewperf benchmarks were executed on computational servers tintin and nestor. The  benchmark failed to execute on NTC-O, OTC-O because some OpenGL extensions were missing. However it successfully ran on NTC-T and it was also executed on tintin with KDE, Gnome and IceWM to compare the three thr ee desktop environments. Table 12: Experimental design for SPECviewperf benchmark. Values in the table give the

number of repetition for each test. NTC-T did not run IceWM because ThinLinc didn’t support it. SPECviewperf Desktop Environment  Nestor 2 2 2

KDE Gnome IceWM

Tintin 2 2 2

NTC-T 2 2 -

As each benchmark was executed several times see table 9, 10 and12. The average R  avg     R avg 

1 n     Ri , n i 1

(1)

of resulting values was taken to evaluate the performance of these benchmarks. Where  Ri is the time taken by each test of the benchmark to execute on the X server. The performance,  P , was defined as the natural logarithm of the mean number of graphical objects plotted during one second interval. It was evaluated as  P    ln R avg   ,

(2)   (2)

where  R avg    is the average number of graphical objects plotted per unit time and s stands for one second (the unit of time). The performance was evaluated in terms of natural logarithm to scale down the variability of results of individual test. Uncertanity of the average value was calculated with the standard deviation as 1 

   R

n

( Ri   R avg  ) , n(n  1)  i 1

(3) 33

 

Since each of the benchmarks executed tests multiple times the resulting uncertainties of averages were low (0.01%). They are not reported here. 5.3 Results The results of the graphic benchmarks Xbench, X11perf and SPECviewperf are discussed in this section. 5.3.1 Xbench

The Xbench simulation executed from KDE environment revealed that the best performance was achieved with NTC-T. NTC-O had slightly higher performance compared to OTC-O, see Figure 14 (a). The average performance of NTC-O relative to the average performance of OTC-O was 12 times higher. The average performance was taken as the average of individual test performances. performances. For NTC-T this ratio was 25. NTC-T was the fas fastest, test, followed by NTC-O and OTC-O in this order, see Figure 15(a). The NTC-T had highest performance, when Xbench simulations were executed from Gnome.  NTC-O had higher performance performance than OTC-O except for five tests 29, 30, 31, 35 and 38 out of forty-one tests executed in the simulation, see Figure 14 (b). The ratio of the average  performances of NTC-T to OTC-O was 22. The same quantit quantityy ffor or NTC-O and OTC-O was 10, see Figure 15 (b). The OTC-O had slightly improved performance for IceWM as compared to KDE and Gnome.  NTC-O had better performance except for ten tests 8, 9, 20, 22, 25, 29, 30, 31, 34 and 38 out of forty-one tests executed in the simulation, see Figure 14 (c). The ratio of average  performance of NTC-O NTC-O to OTC-O was 8, see Figure 15 (c).

34

 

      8       1       6       1

(a)

    e     c     n     a     m     r     o       f     r     e     p

      4       1       2       1       0       1 NTC-O

      8 0

10

20

NTC-T

O TC-O

30

40

test number 

     8      1      6      1

(b)

    e     c     n     a     m     r     o      f     r     e     p

     4      1      2      1      0      1 NTC-O

     8 0

10

20

NTC-T

OTC-O

30

40

test number 

     6      1

(c)

    e     c     n     a     m     r     o      f     r     e     p

     4      1      2      1      0      1 NTC-O

     8 0

10

20

O TC TC-O

30

test number 

Figure 14: Xbench performance on the old thin client (blue circles) and on the new thin client

with (green circles) and without wit hout (red circles) the ThinLinc software installed. The 40 Xbench tests are ordered so that the performance of the old thin client as a function of test number does not decrease in KDE (a), Gnome (b), and IceWM (c). 35

40

 

(a)

    O       C    T     O    o    t    e    v    i    t    a    l    e    r    e    c    n    a    m    r    o     f    r    e    p

   8  .    1 

NTC-O NTC-T OTC-O

   6  .    1    4  .    1    2  .    1    0  .    1

0

10

20

30

40

30

40

30

40

test number 

(b)

   O      C    T    O    o    t    e    v    i    t    a    l    e    r    e    c    n    a    m    r    o    f    r    e    p

   0  .    2 

NTC-O NTC-T

   8  .    1

OTC-O

   6  .    1    4  .    1    2  .    1    0  .    1

0

(c)

   O      C    T    O    o    t    e   v    i    t    a    l    e    r    e    c    n    a    m    r    o    f    r    e    p

10

20 test number 

   0  .    2 

NTC-O OTC-O

   8  .    1    6  .    1    4  .    1    2  .    1    0  .    1

0

10

20 test number 

Figure 15: Xbench performance relative to that of OTC-O for the old thin client (blue circles)

and for new thin client with (green circles) and without (red circles) the ThinLinc software installed. The 40 Xbench tests are ordered so that the performance ratio of the old thin client as a function of test number does not decrease in KDE (a), Gnome (b), and IceWM (c). 36

 

Effect of desktop environment

The Xbench benchmark executed with the NTC-O using KDE, Gnome and IceWM showed that KDE had the highest performance compared to the Gnome and the IceWM. Gnome had slightly lower performance than the KDE, however, the IceWM had lowest performance in the entire three desktop environments, see figure 16 and table 13.

   8    1

KDE Gnome

   6    1   e   c   n   a   m   r   o    f   r   e   p

IceWm

   4    1    2    1    0    1    8 0

10

20

30

40

test number 

Figure 16: KDE, Gnome and IceWM performance graph on NTC-O NTC- O  Table 13:  Ratios of average performances for KDE, Gnome and IceWM desktop

environments.

Desktop environment A

B

Performance ratio  P   

KDE

Gnome

1.7

KDE

IceWM

10.3

Gnome

IceWM

5.7

 A

 P  B

37

 

 

Effect of Remote Display

The effect of the remote display for the Xbench test is plotted in figure 17. The average  performance of Xbench ran locally compared to Xbench ran remotely was 2.36 times higher. The average performance was taken as the average of individual test performances. The slowdown was due to the network latency and bandwidth of the 100Mbit/s twisted pair Ethernet. 

   8    1

Tintin Nestor 

   6    1    e    c    n    a    m    r    o    f    r    e    p

   4    1    2    1    0    1

0

10

20

30

40

test number 

Figure 17: Display performance as a function of Xbench test number. Xbench was started

locally on nestor and remotely on tintin.

38

 

 

5.3.2 X11perf The X11perf benchmark ran from the KDE environment indicated that the highest  performance was achieved with the NTC-T. The NTC-O had slightly higher performance compared to the OTC-O, see figure 18(a). The average performance of the NTC-O relative to the average performance of OTC-O was 26 times higher. The average performance was taken as the average of individual individual test performances. For NTC-T this ratio was 12. NTC-T was the fastest, followed by NTC-O and OTC-O in this order, see figure 19(a). The NTC-T had the highest performance, when X11perf benchmarks were executed from tthe he Gnome. NTC-O had higher performance than OTC-O except for some tests, see figure 18 (b). The ratio of average performances of NTC-T to OTC-O was 20. The same quantity for NTCO and OTC-O was 9, see Figure 19(b). Just like Xbench, the OTC-O had slightly improved performance for IceWM as compared to the KDE and the Gnome. The NTC-O had better performance except for some tests, see Figure 18 (c). The ratio of average performance of NTC-O to OTC-O was 11, see Figure 19 (c).

39

 

     5      1

(a)

    e     c     n     a     m     r     o      f     r     e     p

     0      1

     5

NTC-O NTC-T OTC-O

     0

0

100

200

300

test number 

   5    1

(b)

  e   c    0   n    1   a   m   r   o    f   r   e   p    5

NTC-O NTC-T OTC-O

   0

0

100

200

300

test number 

   5    1

(c)

  e   c    0   n    1   a   m   r   o    f   r   e   p    5

NTC-O OTC-O

   0

0

100

200

300

test number 

Figure 18:  X11perf performance on the old thin client (blue circles) and on the new thin

client with (green circles) and without (red circles) the ThinLinc software installed. The 380 X11perf tests are ordered so that the performance of the old thin client as a function of test number does not decrease in KDE (a), Gnome (b), and IceWM (c). 40

 

(a)

   O      C    T    O    o    t    e    v    i    t    a    l    e    r    e    c    n    a    m    r    o    f    r    e    p

   2

   1

   0

NTC-O

   1   -

NTC-T OTC-O

   2   -

0

100

200

300

test number 

b)

   O      C    T    O    o    t    e    v    i    t    a    l    e    r    e    c    n    a    m    r    o    f    r    e    p

   2    1    0    1      2   -

NTC-O NTC-T

   3   -

OTC-O

0

100

20 0

300

test number 

(c)

   O      C    T    O    o    t    e    v    i    t    a    l    e    r    e    c    n    a    m    r    o    f    r    e    p

   2

   1

   0

   1   -

NTC-O OTC-O

   2   -

0

100

200

300

test number 

Figure 19:  X11perf performance relative to that of OTC-O for the old thin client (blue

circles) and for the new thin client with (green circles) and without (red circles) the ThinLinc software installed. The 380 X11perf tests are ordered so that the performance of the old thin client as a function of test number does not decrease in KDE (a), Gnome (b), and IceWM (c). 41

 

5.3.3 SPECviewperf The results of SPECviewperf benchmark when displayed in the KDE environment on tintin, nestor and NTC-T are in figure 20. The average and median performance ratios of tintin relative to NTC-T were 45 and 20, respectively. The average was highly affected by the snx test for which the ratio ratio was 222. The average performance was taken as the aaverage verage of individual test performances. performances. For nestor nestor corresponding ra ratios tios were 7.7 and 7.11 7.11.. Tintin was the fastest, followed by the nestor and the NTC-T in this t his order.

Tintin/NTC-T

   5

Nestor/NTC-T

  e   c    4   n   a   m   r   o    3    f   r   e   p    2

1

2

3

4

5

6

7

8

test number 

Figure 20: Performance ratios as a function of the SPECviewperf test number, cf. table 14.

Performance of the SPECviewperf displayed on KDE, Gnome and IceWM is in table 14. KDE had the highest performance; Gnome and IceWM were slower in this order. Table 14: SPECviewperf results for KDE, Gnome and IceWM desktop environment.

KDE (Frames/second) 4.19

Gnome (Frames/second) 4.07

IceWM (Frames/second) 4.19

2.28

2.2

2.27

Ensight

Test 2

12.57

12.85

9.07

Lightwave

Test 3

2.24

1.8

2.16

Maya

Test 4

3.84

3.75

3.79

Proe

Te Test st 5

5.29

5.29

5.24

Sw

Test 6

1.19

1.17

1.19

Tcvis

Test 7

2.22

2.19

2.23

Snx

Test 8

42

SPECviewperf Test Number Tests Catia Test 1

 

 

5.4 Discussion The remote display slowed down the performance by a factor of approximately 2.36. For office applications (word processors, spread sheets, etc) this is typically not an issue. If however the graphics performance is critical then the usage of remote displays should be considered carefully. Some OpenGL applications in the SPECviewperf benchmark suits did not execute on thin clients with the original software. The Thinlinc software can be used as a workaround in this case. The performance is however limited. For some applications a performance increase in the order of several magnitudes may be achieved by using specialized graphics accelerators; these are, however, not available for thin clients. For thin clients, solutions like the VirtualGL can be used. In this work, no experiments with VirtualGL were performed. From the three desktop environment considered, KDE was fastest followed by Gnome and IceWM in this order. A personal experience shows that IceWM is fastest for almost all the applications including word processing, Matlab calculation etc. This contradiction is most likely caused by the fact that the t he Xbench , X11perf and SPECviewperf benchmarks test only a subset of graphics operations while user applications like web browsers often use alpha  blending or other other operations that degrade degrade the performanc performancee of thin clients. The ThinLinc on new thin client had improved the performance for most of the applications, however, the performance of NTC-O for some applications were higher than NTC-T for example reorganizing windows on NTC-O is faster than NTC-T. 5.5 Conclusion The experiments compared the graphics performance of selected Linux SBC solutions. The effects of factors like KDE, Gnome, IceWM desktop environments, visualization devices like  NTC-O, NTC-T, OTC-O, and computational servers (tintin, nestor and milou) were evaluated. The result showed that the performance of the deployed software solution NTC-T had higher performance than OTC-O. After NTC-T, the performance of deployed hardware solution NTC-T had higher performance compared to OTC-O. Hence, the new hardware and software have increased computer performance at the MR unit.

43

 

44

 

6

User-perceived performance analysis 6.1 Introduction Performance of the Linux based SBC at the MR-unit was assessed via methods of both qualitative and quantitative research. Structured interview, a qualitative research method, was adopted in which the number of questions in the specific order was presented to a focus group; the answers were collected to yield an estimate of the user experience. The format used for the questions type was open-ended in order to get a broad answer range from the users. 6.2 Methods The questions were posed in two stages; before and after the upgrade of computer infrastructure at the MR unit. The set of questions differed, in the first stage; the questions  presented were structured to learn more about the need for an upgrade. Six users used the computing environment at the MR-unit on a regular basis. Of those, three users used thin clients to connect to nestor nestor in the period from 2008 to 2010. These three users were asked asked a set of pre-selected questions, see table 15. The second set of questions was asked to reveal, whether the upgrade process had resolved the significant problems witnessed before by the end users. Again, three users which directly 45

 

connected with the newly upgraded server based computing environment at the MR unit were interviewed with a pre-set of selected questions see table 16. 6.3 Results The results of open ended structured questions are discussed in this section. User interviewing before upgrade

The table 15 shows questions used in the structured interview and corresponding answers. Table 15: Performance evaluation based on user experience before upgrade

QUESTIONS

ANSWERS   Sometimes a listing of files in a

(i) In which way was the response of the server slow?



directory took 10 seconds or more. Times about 2 or 3 seconds had been

expected. a text typed on a keyboard   Sometimes



to a field in a web browser appeared on the screen after a delay of several seconds.

  In the beginning, the degradation was

(ii) Did the server performance degradation appear randomly during the day or was there a regular pattern?



more or less random. Later, however, the performance degradation was observed on a regular basis.

(iii) At which time of the day was the  performance degradation worst? What were the symptoms?

  Performance degradation was mostly



observed during office hours. The system was less responsive than at other times.   Once, the performance degradation was also observed during a weekend.



46

 

User interview after upgrade

Table 16 shows questions used in the structured interview and corresponding answers.  Table 16: Performance evaluation based on user experience after the upgrade 

QUESTIONS

ANSWERS

(i) Do you feel the server performance is  No (3 users) slow? (ii) How much time does it take to list the 1 second (2 users) files? 2 second (1 user) (iii) Does it perform slowly in the Internet  No (3 users)  browser too? (v) Has the performance improved?

Yes (3 users)

6.4 Discussion The interviews showed that the performance deterioration was not a result of a sudden change of system settings or a system failure. The deterioration happened gradually over several years due to software updates installed over the years. The new software provided more graphically rich environment but, on the other hand, consumed more system resources. 6.5 Conclusion The qualitative research method of structure interviewed with open ended question revealed that the performance of Linux based SBC at the MR unit has improved after the upgrade. 

47

 

48

 

7

Conclusion 7.1 Conclusion The first objective of the thesis work was to evaluate the performance of the existing computing infrastructure at the MR unit. The performance of the system was measured via  benchmarks and user interviews. The first bottleneck identified was the CPU speed. Applications installed at MR unit were also graphics-intensive. The second bottleneck, with respect to the graphics intensive applications, includes the network latency of the X11  protocol and the subsequent performance of the old thin clients. An upgrade of both the computational server and the thin clients were suggested. The second objective of the thesis work was to upgrade the IT infrastructure at the MR unit. Upgrade involved the selection and setup of the new server and the thin clients. The analysis of the new system performance showed that the objective to increase the performance of the IT infrastructure has been reached. The evaluation after the upgrade involved performance analysis via quantitative and qualitative methods. For the former benchmarks were used while for the latter structured interviews with open-ended questions were performed. The results showed that the new configuration had improved the performance.

49

 

Appendix A Xbench code R script used to extract information from Xbench output files

type = $2; for (i =1; i <=4; i++) rategetline; = $3;  printf (“%e, \”%s\n”, rate, type);  R script to plot figures

# Reading data file in R dF <- read.csv("Xb_ read.csv("Xb_kde_data.cs kde_data.csv", v", header=TRUE); # Fujitsu computation yF <- as.real(log(dF[ , 1])) # Igel computation yI <- as.real(log(dF[ , 2])) # Thinlinc computation yT <- as.real(log(dF[ , 3])) # Plotting iI <- sort(yI, index.return=T)$ix  par(tck=1)  plot (yF[iI], type="p", pch=19, pch=19, col="red", xlab="test number", number", ylab="performance" ylab="performance"))  points (yI[iI], type="p", pch=19, pch=19, col="blue")  points (yT[iI], type="p",pch=19, type="p",pch=19, col="green"); Performance ratio graph

# Reading data file in R dF <- read.csv("Xb_ read.csv("Xb_kde_data.cs kde_data.csv", v", header=TRUE); # Fujitsu computation yF <- as.real(log(dF[ , 1])) # Igel computation yI <- as.real(log(dF[ , 2])) #yTThinlinc computation <- as.real(log(dF[ , 3])) # Plotting rF <- yF / yI rI <- yI / yI rT <- yT / yI iI <- sort(rF, index.return=T)$ix  par(tck=1)  plot(rF,type="p",pch=19,  plot(rF,type="p",pch=1 9, col="red", xlab="test nu number", mber", ylab="performance ylab="performance relative to Igel TC")  points(rI, type="p",pch=19,col="blue") type="p",pch=19,col="blue")  points(rT, type="p",pch=19 type="p",pch=19 col="green");

50

 

Table 17: Xbench test indexes for figure 16 and 17. The 40 Xbench tests were ordered with

the performance of the OTC-O as a function of test numbers for KDE, Gnome and IceWM, figure 14 and 15. Xbench tests indexes for figure16 and 17 Test number Test1 Test2 Test3 Test4 Test5 Test6 Test7 Test8 Test9 Test10

Test  Name lines10 lines100 lines400 dashlines10 dashlines100 dashlines400 widelines10 widelines100 widelines400

Xbench tests indexes for Kde Test number Test1 Test2 Test3 Test4 Test5 Test6 Test7 Test8 Test9 Test10

rectangle10 Test11

Test11 rectangle100

Test12 Test13 Test14 Test15 Test16 Test17 Test18 Test19 Test20 Test21 Test23

rectangle400 fillrectangle10 fillrectangle100 fillrectangle400 tilledrectangel10 tilledrectangel100

Test13 Test14 Test15 Test16 Test17 Test18 Test19 Test20 Test21 Test23

Test26 Test27 Test28 Test29 Test30 Test31 Test32 Test33 Test34 Test35 Test36 Test37 Test38 Test39 Test40 Test41

screencopy400 Scroll bitmapcopy10 bitmapcopy100 bitmapcopy400 image_string complex1

Test25

fillrectangle10 fillrectangle100 fillrectangle400 tilledrectangel10 tilledrectangel100 tilledrectangel400 stiplerectangle10 stiplerectangle100 stiplerectangle400 invertedreactangle10 invertedreactangle10 0

Test12

tilledrectangel400 stiplerectangle10 stiplerectangle100 stiplerectangle400 invertedreactangle 10 invertedreactangle 100 invertedreactangl4 00 arcs10 arcs100 arcs400 filledarcs10 filledarcs100 filledarcs400 filledpoly100 screencopy10 screencopy100

Test24

Test name

Xbench tests indexes for Gnome Test number Test1 Test2 Test3 Test4 Test5 Test6 Test7 Test8 Test9 Test10 Test11 Test12

invertedreactangl400 lines10 lines100 lines400 arcs10 arcs100 arcs400 filledarcs10 filledarcs100 filledarcs400

Test13 Test14 Test15 Test16 Test17 Test18 Test19 Test20 Test21 Test23

filledpoly100 Test24

Test name fillrectangle10 fillrectangle100 fillrectangle400 tilledrectangel10 tilledrectangel100 tilledrectangel400 stiplerectangle10 stiplerectangle100 stiplerectangle400 invertedreactangle1 0 invertedreactangle1 00 invertedreactangl40 0 filledpoly100 screencopy10 screencopy100 screencopy400 lines10 lines100 lines400 arcs10 arcs100

screencopy10 Test26 Test27 Test28 Test29 Test30 Test31 Test32 Test33 Test34 Test35 Test36 Test37 Test38 Test39 Test40 Test41

rectangle400 bitmapcopy10 bitmapcopy100 bitmapcopy400 image_string complex1 Scroll

Test name fillrectangle10 fillrectangle100 fillrectangle400 tilledrectangel10 tilledrectangel100 tilledrectangel400 stiplerectangle10 stiplerectangle100 stiplerectangle400 dashlines10

Test11 dashlines100 Test12 Test13 Test14 Test15 Test16 Test17 Test18 Test19 Test20 Test21 Test23

dashlines400 widelines10 widelines100 widelines400 rectangle10 rectangle100 rectangle400 invertedreactangle10 invertedreactangle100 invertedreactangl400 filledpoly100

Test24 filledarcs10

Test25 screencopy100 screencopy400 dashlines10 dashlines100 dashlines400 widelines10 widelines100 widelines400 rectangle10 rectangle100

Test number Test1 Test2 Test3 Test4 Test5 Test6 Test7 Test8 Test9 Test10

arcs400 Test24

Test25

Xbench tests indexes for Icewm

screencopy10 Test25

Test26 Test27 Test28 Test29 Test30 Test31 Test32 Test33 Test34

filledarcs100 filledarcs400 dashlines10 dashlines100 dashlines400 widelines10 widelines100 widelines400 rectangle10 rectangle100

Test26 Test27 Test28 Test29 Test30 Test31 Test32 Test33 Test34

screencopy100 screencopy400 lines10 lines100 lines400 arcs10 arcs100 arcs400 filledarcs10 filledarcs100

Test35 Test36 Test37 Test38 Test39 Test40 Test41

rectangle400 bitmapcopy10 bitmapcopy100 bitmapcopy400 image_string complex1 Scroll

Test35 Test36 Test37 Test38 Test39 Test40 Test41

filledarcs400 bitmapcopy10 bitmapcopy100 bitmapcopy400 image_string complex1 Scroll

51

 

Appendix B X11perf code R script to plot figures

# Reading data file in R dF <- read.csv("x1-kde read.csv("x1-kde-data.csv", -data.csv", header=TRUE); #yFFujitsu computation, 1])) <- as.real(log(dF[ # Igel computation yI <- as.real(log(dF[ , 2])) # Thinlinc computation yT <- as.real(log(dF[ , 3])) # Plotting iI <- sort(yI, index.return=T)$ix  par(tck=1)  plot (yF[iI], type="p", pch=19, pch=19, col="red", xlab="test number", number", ylab="performance" ylab="performance"))  points (yI[iI], type="p", pch=19, pch=19, col="blue")  points (yT[iI], type="p",pch=19, type="p",pch=19, col="green"); Performance ratio graph

# Reading data file in R dF <- read.csv("x1-kde read.csv("x1-kde-data.csv", -data.csv", header=TRUE); # Fujitsu computation yF <- as.real(log(dF[ , 1])) # Igel computation yI <- as.real(log(dF[ , 2])) # Thinlinc computation yT <- as.real(log(dF[ , 3])) # Plotting rF <- yF / yI rI <- yI / yI rT <- yT / yI iI <- sort(rF, index.return=T)$ix  par(tck=1)  plot(rF,type="p",pch=19,  plot(rF,type="p",pch=1 9, col="red", xlab="test nu number", mber", ylab="performance ylab="performance relative to Igel TC")  points(rI, type="p",pch=19,col="blue") type="p",pch=19,col="blue")  points(rT, type="p",pch=19 type="p",pch=19 col="green");

52

 

Appendix C Table 18: Technical specification of new and old thin clients at the MR unit.

Specification

Fujitsu S550

IGEL-2100 LX Smart

CPU

1GHz

400 MHz

RAM

1 GiB

236 MiB

Cache

256 KiB

128 KiB

 Network

1000 Mb/s

100 Mb/s

Graphics card

AMD Radeon X1250

VGA CHIPSET VIA CLE266

Table 19: Considerd alternatives for the computational server.

Product Description

HP Z800

HP G6

Type

Workstation

Server

Processor

2 x Intel Xeon Quad 2 x Intel Xeon Quad core 2 x Intel Xeon Quad core E5560 X5550 core E5530 2.8 GHz 2.6 GHz 2.4 GHz

Cache

8 MB L3-cache

16 MB L3 cache

8 MB L3 cache

RAM

6 GB (installed) / 192 GB (max) - DDR3 SDRAM - ECC - 1333 MHz

12 GB (installed) / 144 GB (max) - DDR3 SDRAM - 1333 MHz PC3-10600

12 GB (installed) / 96 GB (max) - DDR3 SDRAM - Advanced ECC - 1066 MHz PC3-10600

Disks drives

2 x 500 GB - standard 1 x 1 TB - standard - 1 x 1 TB - standard Serial ATA-300 Serial ATA-300 - Serial ATA-300

Graphics controller

 Nvidia Quadro NVS ATI ES1000 295 53

ProLiant

DL380

Fujitsu Primergy TX

Server

ATI

 

adapter Communicat  Network adapter - PCI  Network adapter - PCI  Network Express - Ethernet, Express - Ethernet, Fast Ethernet, Fast Ethernet, ion Fast Ethernet, Gigabit Ethernet - Ethernet Ports: 2 x Gigabit Ethernet

Ethernet, Gigabit Gigabit Ethernet Ethernet - Ethernet Ethernet Ports: 2 x Ports: 4 x Gigabit Gigabit Ethernet Ethernet

Table 20: Considered alternatives for thin clients.

S450

S550

S500

Processor

800 MHz

1 GHz

1 GHz

RAM

1 SODIMM

1 DIMM

1 FLASH

Maximum supported RAM

1 GiB

2 GiB

2 GiB

Graphics

1920 x 1200 Pixel 2048 x 1536 Pixel

2048 x 1536 Pixel

Internal HDD module

Yes

Yes

No

PCI Slot

Yes

Yes

No

54

 

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