Application Note. A Performance Comparison of Dialogic DM3 Media Boards for PCI Express and PCI

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1 A Performance Comparison of Dialogic DM3 Media Boards for PCI Express and PCI

2 Executive Summary This application note compares the performance of the Dialogic DM3 Media Boards for PCI with the newer DM3 Media Boards for PCI Express using recently conducted latency tests, and discusses how reducing latency can improve system performance and the quality of audio conversations.

3 Table of Contents Introduction... 2 PCI Express Features... 2 Dialogic DM3 Media Boards for PCI Express... 2 Performance Testing... 2 Latency Tests and Results... 2 Factors Contributing to Improved Performance... 4 Summary.... 4

4 Introduction Dialogic has completed performance analyses to determine how the Dialogic DM3 Media Boards for PCI Express (PCIe) compare to the DM3 Media Boards for PCI. This application note discusses the test results, factors that contribute to the improved DM3 Media Boards for PCIe performance, and the ways in which developers could benefit from migrating to DM3 Media Boards for PCIe. PCIe technology is a highly scalable, switched, point-to-point, serial I/O interconnect technology that maintains software compatibility with PCI. PCIe is a standard local I/O bus for a wide variety of computing platforms. The PCI Special Interest Group (PCI-SIG) appointed PCIe as the successor to PCI. It is anticipated that PCIe will replace much of the existing PCI, PCI-X, and proprietary in-the-box bus architectures over the next decade. Many PC manufacturers, such as Dell and HP, currently offer hybrid chassis that have PCI and PCIe slots on their server and desktop offerings. In the coming years, these manufacturers are likely to decrease the ratio of PCI slots to PCIe slots in the hybrid chassis. PCI Express Features At a basic technical level, PCIe provides the following notable features: Point-to-point serial interconnections between devices High bandwidth per pin Low power consumption and power management functions Device hot-pluggability and hot-swap PCI-level error handling and advanced error reporting Small connectors for space savings Compatibility with PCI at the software layers (but not at the board or connector level) Dialogic DM3 Media Boards for PCI Express Since early 2006, Dialogic has transitioned many board level solutions to PCIe. As PCIe gains acceptance among developers of communications solutions, and as the ratio of PCI to PCIe slots continues to decrease, customers are likely to be motivated to upgrade to PCIe platforms. The Dialogc DM3 Media Boards are available on three platforms: PCI, cpci and, the newest member, PCIe. The DM3 Media Boards are combined media and network interface suitable for developers who choose to build and globally deploy some of the highest density media server solutions for the enterprise and service provider networks. The three platforms offer robust media feature sets, including voice processing, speech recognition, fax, and conferencing capabilities, combined with an extensive suite of network protocols in a single PC slot. Performance Testing Prior to the release of the PCIe versions of the DM3 Media Boards which include single, dual and quad T and/or E network interface spans testing was completed by Dialogic to compare the performance of the DM3 Media Boards for PCIe versus that of the existing DM3 Media Boards for PCI. The following equipment was used for these tests: Boards: Dialogic DM/V3600BP Media Board (PCI form factor) Dialogic DM/VBTEPEQ Media Board (PCIe form factor) System: Dell PowerEdge 6850 Processor: Intel Xeon 740M, 3.4 GHz GB Memory 3 PCI/X slots 4 PCIe slots Latency Tests and Results Figure shows the average play latency of a DM3 Media Board for PCI versus the newer DM3 Media Board for PCIe. The tests that completed ran multiple channels of play, playing voice files from the telecom server (host) to the voice resources on Dialogic DM/V-B Media Boards, and determining average latency versus the number of channels used in each test. Latency is defined as the time between the voice packet being transmitted and when it reaches its destination. For the tests performed in this application note, latency is the measurement between the time the voice is completely processed and sent from the host to when it reaches the board. For this case (see Figure ), no termination conditions were set; play continues to the end of the files, until the end of the test. When comparing the DM/V-B Media Board for PCIe with its predecessor DM/V-B Media Board for PCI, the test shows that PCIe offers a lower latency, and that, as more channels are used, its latency remains relatively constant and desirably lower than PCI latency. 2

5 250 Average Latency DM3 PCI DM3 PCIe Number of Channels Figure. Average Latency During Testing (No Terminations Conditions) Two other test scenarios were performed. In Figure 2, tests were again conducted by playing voice files from the host to DM/V-B Media Boards. However, in this instance, plays were terminated when a maximum amount of time (in this testing, 000 msec) was reached. The chart displays how the increase in density of the test produced a flat latency line, so the latency remains low as the system/application grows larger. The predetermined length of the test meant that less processing was required to perform this test, resulting in less latency overall (versus the other two tests performed) for each board Average Latency DM3 PCI DM3 PCIe Number of Channels Figure 2. Average Latency During Test (Maximum Time) 3

6 In Figure 3, plays were terminated when MAXDTMF (that is, two DTMFs) was detected. This testing resulted in slightly more processing, since Dual Tone Multi-Frequency (DTMF) needed to be detected to stop the playing of the files. However, as the chart shows, the DM/V-B Media Board for PCIe again achieved better results than the DM/V-B Media Boards for PCI, with the DM/V-B Media Board for PCIe producing less latency as the system/application density grew Average Latency DM3 PCI DM3 PCIe Number of Channels Figure 3. Average Latency During Test (Maximum DTMF) Factors Contributing to Improved Performance One factor contributing to the improved performance of the DM3 Media Boards for PCIe is that they have more a powerful Control Processor (CP) than the DM3 Media Boards for PCI, resulting in real-time voice processing and better overall system performance. Another factor is that the DM3 Media Boards for PCIe have a powerful new ASIC with a more efficient memory management capability that boosts DSP performance. This ASIC improves onboard data transfer and overall DSP performance by 50% or more versus Dialogic DM3 Media Boards for PCI. Summary Excessive latency creates bottlenecks, thus decreasing effective bandwidth. In the three test scenarios provided in this application note, average latency is reduced with the Dialogic DM/V-B Media Board for PCIe versus its PCI counterpart, leading to higher voice quality and an improvement in overall system performance. Factors contributing to the Dialogic DM3 Boards for PCIe improved latency performance are its more powerful Control Processor, which improves processing ability, and its powerful new ASIC with more efficient memory management capability that boosts the board s overall performance. 4

7 Dialogic Corporation 9800 Cavendish Blvd., 5th floor Montreal, Quebec CANADA H4M 2V9 INFORMATION IN THIS DOCUMENT IS PROVIDED IN CONNECTION WITH PRODUCTS OF DIALOGIC CORPORATION OR ITS SUBSIDIARIES ( DIALOGIC ). NO LICENSE, EXPRESS OR IMPLIED, BY ESTOPPEL OR OTHERWISE, TO ANY INTELLECTUAL PROPERTY RIGHTS IS GRANTED BY THIS DOCUMENT. EXCEPT AS PROVIDED IN A SIGNED AGREEMENT BETWEEN YOU AND DIALOGIC, DIALOGIC ASSUMES NO LIABILITY WHATSOEVER, AND DIALOGIC DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY, RELATING TO SALE AND/ OR USE OF DIALOGIC PRODUCTS INCLUDING LIABILITY OR WARRANTIES RELATING TO FITNESS FOR A PARTICULAR PURPOSE, MERCHANTABILITY, OR INFRINGEMENT OF ANY INTELLECTUAL PROPERTY RIGHT OF A THIRD PARTY. Dialogic products are not intended for use in medical, life saving, life sustaining, critical control or safety systems, or in nuclear facility applications. Dialogic may make changes to specifications, product descriptions, and plans at any time, without notice. Dialogic is a registered trademark of Dialogic Corporation. Dialogic s trademarks may be used publicly only with permission from Dialogic. Such permission may only be granted by Dialogic s legal department at 9800 Cavendish Blvd., 5th Floor, Montreal, Quebec, Canada H4M 2V9. Any authorized use of Dialogic s trademarks will be subject to full respect of the trademark guidelines published by Dialogic from time to time and any use of Dialogic s trademarks requires proper acknowledgement. The names of actual companies and products mentioned herein are the trademarks of their respective owners. Dialogic encourages all users of its products to procure all necessary intellectual property licenses required to implement their concepts or applications, which licenses may vary from country to country. Copyright 2008 Dialogic Corporation All rights reserved. 05/