Accelerating Server. and. Application Performance

Transcription

1 Accelerating Server and Application Performance

2 Table of Contents INTRODUCTION...1 NEW ADAPTER ARCHITECTURE ENABLES BETTER PERFORMANCE...2 Figure 1. Protocol stack with Alacritech SLIC technology...2 FULL STANDARDS COMPATIBILITY FOR TODAY AND THE FUTURE...2 PERFORMANCE TESTS SCORE UP TO 800% IMPROVEMENT WITH ALACRITECH ADAPTERS...3 Figure 2. ZD Labs server adapter test bed configuration...3 SUMMARY OF TEST RESULTS... 4 Figure 3. P/E Index ratios for Alacritech versus Intel Gigabit adapter...4 TEST RESULTS THROUGHPUT... 5 TEST RESULTS CPU UTILIZATION...6 TEST RESULTS LATENCY... 7 ALACRITECH REMOVES OTHER CONVENTIONAL SERVER ADAPTER BOTTLENECKS TO ACHIEVE GIGABIT PERFORMANCE...8 MEMORY TRAFFIC... 8 Figure 4. Memory traffic comparison...8 CPU INTERRUPTS... 9 Figure 5. CPU errupt comparison...9 PCI TRAFFIC Figure 6. PCI traffic comparison...10 SUMMARY Alacritech, Inc. All rights reserved. Alacritech, the Alacritech logo, SLIC Technology, and the SLIC Technology logo are trademarks of Alacritech, Inc. in the United States and Europe. All other trademarks or symbols contained herein are or may be the property of their respective owners. THIS PUBLICATION IS PROVIDED AS IS WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT. CHANGES ARE PERIODICALLY ADDED TO THE INFORMATION HEREIN; THESE CHANGES WILL BE INCORPORATED IN NEW ADDITIONS OF THE PUBLICATION. ALACRITECH, INC. MAY MAKE IMPROVEMENTS AND/OR CHANGES IN THE PRODUCT(S) AND/OR THE PROGRAMS DESCRIBED IN THIS PUBLICATION AT ANY TIME.

3 Introduction Network adapters traditionally are the most invisible, least considered and dare we say it? boring elements of a network system. On the surface, one might reasonably ask what there is to discuss about a commodity product that provides the physical erface between network wiring and a PC or server. The performance of most adapters is similar. So is the fundamental design architecture, which has not changed for two decades. Results from performance tests of new network adapters typically reveal incremental improvements of just 5%. Whenever server bottlenecks occur, the typical solution involves either buying a larger server with extra processors or investing in Gigabit Ethernet. Alacritech has a practical solution to the bottleneck issue. Standard lab performance tests of Alacritech network adapters found up to an 800% improvement over popular adapter brands. Because of different factors, real-world performance improvements vary from 15% up to 100%. The dramatic boost stems from offloading network protocol processing from the host computer to an Alacritech adapter. Alacritech adapters employ a new architecture, called SLIC (Session-Layer Interface Card) technology, which uses an innovative application-specific egrated circuit (ASIC) for protocol processing. Alacritech adapters, based on SLIC technology, improve host processor efficiency, increase data throughput and reduce latency. Alacritech adapters are 100% compatible with industry standards including existing LAN infrastructure, PC hardware and software, switches, hubs and routers. Network managers thus can use Alacritech adapters to achieve the performance of Gigabit Ethernet for the bandwidth-ensive applications without the expensive and time-consuming process of upgrading network infrastructure. Independent tests of adapters from Alacritech and Intel Corporation performed by ZD Labs reinforce the dramatic performance improvements delivered by this innovative solution. According to ZD Labs, In all of the tests conducted, the Alacritech 100x4 server adapters outperformed the Intel PRO/100+ server adapters and utilized fewer server CPU resources. ZD Labs measured overall performance of server adapters by testing data throughput and server CPU utilization. An aggregate presentation of all these data is the Performance/Efficiency (P/E) Index Ratio. This industry-standard ratio is throughput divided by server CPU utilization. The ratio captures the benefits of higher throughput and lower CPU utilization. A higher ratio is better. On average for non-gigabit tests, Alacritech scored a P/E Index Ratio of 15.5 while Intel scored 3.12 a performance improvement by Alacritech of more than 400%. Alacritech performed an average of 238% better than Intel s PRO/1000 Gigabit Ethernet adapter. This white paper presents findings of standard benchmark testing and explains how Alacritech technology dramatically boosted server adapter performance Alacritech, Inc. Technology White Paper

4 New Adapter Architecture Enables Better Performance Alacritech improved adapter performance by moving network protocol processing from the server CPU to an ASIC chip called an Internet Protocol Processor (IPP). The IPP resides on the Alacritech server adapter. The concept of offloading applications from a server CPU to an external card is not new. Common examples include SCSI adapters for disk processing and graphics adapters for graphics acceleration. The Alacritech solution should not be confused with so-called elligent network adapters; the latter are mere iterations of 20-year-old adapter technology. Alacritech spent two years developing a new adapter technology called Session-Layer Interface Card (SLIC technology). Figure 1 shows the protocol processing functionality provided by SLIC hardware with Windows NT. The Alacritech solution provides a fast path for many network transactions, offloading protocol processing from the host. Moving protocol processing to an Alacritech server adapter dramatically improves adapter and server performance. TCP/IP management and control remain on the host. Alacritech adapters are deployed in the same manner as legacy adapters. Figure 1. Protocol stack with Alacritech SLIC technology 5. Session SMB 4. Transport 3. Network 2. Data Link 1. Physical NetBIOS TCP/IP SLIC Driver Alacritech SLIC Other Transport Protocols TDI boundary NDIS boundary Source: Alacritech, Inc. Full Standards Compatibility for Today and the Future Alacritech SLIC technology is 100% compatible with IEEE Ethernet standards, including legacy network adapters and other existing LAN infrastructure, PC hardware and software, switches, hubs and routers. Alacritech does not use proprietary schemes such as jumbo frames, which are incompatible with existing standards and equipment. Driver updates will allow network managers to update IPP firmware to add new functionality while ensuring compatibility with future changes to standards Alacritech, Inc. Technology White Paper 2

5 Performance Tests Score up to 800% Improvement with Alacritech Adapters Alacritech commissioned ZD Labs to test adapter performance using ZD Benchmark Operation s industry-standard NetBench 6.0 software. Tests pitted several configurations of Alacritech adapters against Intel Corporation adapters 1 on a test bed illustrated in Figure 2. Figure 2. ZD Labs server adapter test bed configuration Mhz PII clients running Windows 98 SE Mhz PII clients running Windows 98 SE A Gigabit link was used to connect the switches to create a single segment for the Intel Gigabit Adapter test Depending on the test, the server was connected to the switches via 4 100Mbps, 8 100Mbps, Mbps, or Mbps full-duplex connection(s) Mbps fullduplex connections to the clients FastEthernet Switches configured with 0, 2, 4, or 8 VLANs depending on the test Test Server containing NICs under test Source: ZD Labs The test bed server was a Compaq Proliant 6400R server with one 500Mhz Intel Pentium III Xeon processor; 1GB of RAM, and a RAID controller configured with four drives in a RAID5 stripe to hold NetBench data. Tests were repeated with the server running Microsoft Windows NT Server 4.0 with service pack 5, and Windows 2000 Server. ZD Labs designed the test suite for server network adapters. Placing the 100MB test file in the server file cache bypassed bottlenecks by avoiding the server disk subsystem. During each of five tests, clients issued file read requests of a specified size to the server. Each test used a different request size, including 256, 2048, 8192, and bytes. Larger request sizes reflect larger data files moving over a network, such as HTTP for web access, 1 Alacritech ernally tested other vendors adapters with NetBench, including Adaptec, Compaq, D-Link and SMC. The results were similar to those described below for Intel adapters Alacritech, Inc. Technology White Paper

6 or network-based data for word processing, spreadsheet, presentation, CAD/CAM and video applications. Summary of Test Results Alacritech 100x4 server adapters outperformed Intel adapters in every NetBench test performed by ZD Labs. The most pronounced improvements showed in tests running the larger 32Kbyte and 64Kbyte request sizes, which are typical of large data files used by modern corporate and e-commerce applications. For example, eight-network test results for larger request sizes showed much faster throughput for Alacritech adapters 873 Mbits/sec versus 425 Mbits/sec for Intel PRO/100+ adapters. Response time for Alacritech adapters was half the duration of Intel s. The most dramatic difference was CPU utilization. Intel adapters fully saturated the server with 100% utilization while Alacritech s CPU utilization for the largest request size was just 23%. Overall, Alacritech s P/E Index Ratio was 812% better than Intel s. Results were equally telling for Alacritech adapter versus Intel s PRO/1000 Gigabit server adapter. Four Alacritech 4-port adapters moved data with the largest request size at a rate of 1572 Mbits/sec compared to the Intel s Gigabit Ethernet adapter s sub-gigabit rate of 847 Mbits/sec. Alacritech retained a similar response time advantage. And while Intel s PRO/1000 improved CPU utilization to 97% at the largest request size, Alacritech adapters used just 33% of the CPU. Overall, Alacritech s P/E Index Ratio was 446% better than Intel s for the Gigabit tests. Figure 3. P/E Index ratios for Alacritech versus Intel Gigabit adapter 2 P/E Index Ratio -- Gigabit Tests with 64K Request Size Intel Alacritech Alacritech Intel P/E Index Ratio Source: Alacritech, Inc. 2 Test results employ Microsoft Windows NT on the server with request size of bytes. Windows 2000 test results are comparable Alacritech, Inc. Technology White Paper 4

7 Test Results Throughput Throughput measures the transfer rate of data packets-per-second moving through the network adapter. Larger throughput numbers are better. All adapters showed a better transfer rate with larger request sizes. Alacritech adapters' throughput generally was about twice the rate of Intel adapters. These results show that high-performance Alacritech adapters provide better throughput than Gigabit Ethernet without requiring expensive and time-consuming infrastructure upgrades such as Gigabit switches and special network wiring. Throughput: Eight Networks Mbits/sec Alacritech SLIC (NT 4.0) Intel Pro/100+ (NT 4.0) Request Size Source: ZD Labs Throughput: Four Alacritech 100x4 server adapters vs. single Intel Gigabit server adapter Mbits/sec Request Size Alacritech 100x4 Intel PRO/1000 Source: ZD Labs Alacritech, Inc. Technology White Paper

8 Test Results CPU Utilization CPU utilization measures how much of the server central processor was used for a particular data transfer to network clients. A lower CPU utilization is better. Alacritech showed dramatically lower CPU utilization during larger request sizes. CPU Utilization: Eight Networks percent Request Size Alacritech SLIC (NT 4.0) Intel Pro/100+ (NT 4.0) Source: ZD Labs CPU Utilization: Four Alacritech 100x4 server adapters vs. single Intel Gigabit server adapter percent Alacritech 100x4 Intel PRO/ Request Size Source: ZD Labs Alacritech, Inc. Technology White Paper 6

9 Test Results Latency Latency is a measure of time required to complete a transaction across the network, such as the delay between a client requesting data and a server returning the data. Lower latency equates to faster throughput and application performance. Latency can occur even if just one client is accessing a non-saturated server. To illustrate, Alacritech performed a simple file copy test. The test measured the duration of copying a 127 MB file from one remotely mapped directory to another remotely mapped directory, bypassing client disk access. The 500 Mhz Pentium III server had a Xeon processor, 1GB of RAM and a Symbios RAID controller with one 9 GB drive. The server ran Windows NT 4.0 Server with service pack 5. The client used a 400 Mhz Celeron processor with 64 MB of RAM and Windows NT 4.0 with service pack 5. The file copy test was repeated with an Intel PRO 100+ and one port on an Alacritech 4-port adapter. Latency test results show the file copy took 2.5 times longer with the Intel adapter. Alacritech dramatically cut latency, providing much better performance for this common application. 127 MB File Copy Time Intel Alacritech Alacritech Intel Seconds Source: Alacritech, Inc Alacritech, Inc. Technology White Paper

10 Alacritech Removes Other Conventional Server Adapter Bottlenecks to Achieve Gigabit Performance Alacritech also engineered its breakthrough server adapters to resolve server performance bottlenecks other than the CPU processor. Three common bottlenecks induced by conventional adapter architectures include memory traffic, CPU errupts and PCI traffic. Memory Traffic Memory traffic passes over a CPU-memory bus between a server CPU and its main RAM bank. The bus carries a finite amount of shared traffic including network protocol processing, operating system and application processes. The inefficient protocol-related processing caused by conventional network adapters bogs down system performance. The performance hit can be significant, even for Intel Pentium II or III servers with caching. Just one 64Kbyte transfer can invalidate all contents of the Level 1 cache and about 40% of the Level 2 cache. This erference reduces the cache s hit rate for application processes and diverts memory access across the memory bus to main RAM a route that is 10 times slower than using the cache. Alacritech reduces the number of data transfer frame transactions from seven to one (see Fig. 4), which frees the memory bus and server for faster application processing. Figure 4. Memory traffic comparison Conventional NIC 1 NIC Driver Buffers Alacritech SLIC 1 NIC Driver Buffers NDIS boundary TCP/IP Buffers NDIS boundary TCP/IP Buffers L2 Cache 5 TDI boundary L2 Cache TDI boundary 6 Destination Destination 7 Source: Alacritech, Inc. The frame processes for a conventional adapter include (1) write from NIC to NIC driver buffer; (2) read from NIC driver buffer o cache; 3 (3) read from TCP/IP buffer o cache; 4 (4) write from cache to TCP/IP buffer; (5) read from TCP/IP buffer o cache; 5 3 Transactions 2, 3 and 4 may not be required with Microsoft Windows 2000 using adapters that support the NDIS 4 routine NdisMIndicateReceivePacket. 4 Transaction 3 fills the cache line before transaction 4; similarly, transaction 6 fills cache line before transaction 7. 5 Transaction 5 is not required if the cache line is still valid from transaction 3. Transaction 5 may occur twice if the cache line is invalidated between checksum calculation and moved to destination Alacritech, Inc. Technology White Paper 8

11 (6) read from destination o cache; and (7) write from cache to destination. Since Alacritech performs protocol processing on the adapter, frame processes require just one transaction: the adapter writes the frame directly to the final destination. The Alacritech architecture reduces memory traffic related to protocol processing. Memory traffic is freed to process applications faster. CPU Interrupts A computer processor can do just one thing at a time. Whenever a peripheral device requires the CPU, the CPU errupts its current process to attend the new request. The process of polling peripherals and performing their multiple concurrent requirements retards a CPU s availability to process applications. To no surprise, conventional network adapters generate many errupts. Interrupts must be read over the PCI bus, which is relatively slow and busy servicing other peripherals. Interrupts also invalidate cache lines. These factors slow overall system performance. For example, consider errupt overhead generated by conventional and Alacritech adapters for a Server Messaging Block (SMB) Session Data Unit (SDU) file transfer of 64 Kbytes. Fig. 5 illustrates this transfer as 44 frames of 1500 bytes per frame. As a conservative estimate, the conventional adapter scenario assumes four frames per errupt. This scenario omits factoring other errupts stemming from TCP acknowledgements. The resulting errupt rate of 2,140 per second often will be higher. Alacritech adapters pose virtually no errupt overhead to a CPU. Alacritech performs protocol processing on the adapter so the SMB SDU scenario creates just two errupts: one to start and one to end a transaction. Alacritech cuts the rate of errupts to 390 per second an 82% reduction from use of a conventional adapter. Figure 5. CPU errupt comparison Conventional NIC Alacritech SLIC KB SMB SDU: bytes each 64 KB SMB SDU: bytes each Source: Alacritech, Inc Alacritech, Inc. Technology White Paper

12 PCI Traffic The PCI bus congestion is similar to issues discussed for memory traffic. Adapters plug o the PCI bus, which facilitates reads five times slower than across the CPU memory bus, and 50 times slower than a read from a CPU cache. Reads across a PCI bus drag system performance. Minimizing reads across the PCI bus will speed system performance. Conventional adapters generate three transactions across the PCI bus for each frame transfer from the NIC to the NIC driver buffer. Fig. 6 shows these transactions: (1) read from descriptor ring to NIC (status and poer); (2) write from NIC to NIC driver buffer (frame); and (3) write from NIC to descriptor ring (updated status). An Alacritech adapter performs all protocol processing and reduces transactions to just one: writing the frame directly to destination. Alacritech also eliminates the read across the PCI bus. This economy boosts network throughput, frees PCI bus bandwidth for other peripherals and frees the CPU for faster processing of business applications. Figure 6. PCI traffic comparison Conventional NIC Alacritech SLIC Descriptor Ring Destination NIC Driver Buffers Source: Alacritech, Inc. Reducing other conventional adapter bottlenecks such as memory traffic, CPU errupts and PCI traffic improves overall system performance. They are more reasons why network managers can rely on Alacritech adapters to achieve the performance of Gigabit Ethernet without the expensive and time-consuming process of upgrading network infrastructure Alacritech, Inc. Technology White Paper 10

13 Summary Server network adapters may be the most overlooked component of a network but their affect on system performance is profound. Conventional adapters drag down performance because they force the server CPU to process network protocols. New, SLIC-based adapters from Alacritech perform all network protocol processing. They offer a 100% standards-compatible solution for resolving server adapter bottlenecks. By using server adapters from Alacritech, organizations can experience better host processor efficiency, increase network data throughput and reduce application latency. Alacritech adapters provide the performance benefits of Gigabit Ethernet without requiring an infrastructure upgrade. Alacritech adapters work with legacy adapters and other LAN infrastructure, PC hardware and software, switches, hubs and routers. The simplicity of using Alacritech adapters makes them a low-risk path to Gigabit Ethernet and an ideal solution for meeting the rigorous performance requirements of e-commerce. ASIC application-specific egrated circuit CAD/CAM computer-aided design/computer-aided manufacturing CPU central processing unit HTTP Hypertext Transfer Protocol IPP Internet protocol processor ISR errupt status register LAN local area network NIC network erface card PCI peripheral component erconnect P/E Index Ratio Performance/Efficiency Index Ratio RAID Redundant Array of Independent Disks RAM Random Access Memory SCSI small computer system erface SDU session data unit SLIC session layer erface card SMB sever messaging block TCP/IP Transmission Control Protocol/Internet Protocol Alacritech, Inc. Technology White Paper

14 Part Number: DOC MKT 12/00 Pred in the United States. Alacritech, Inc. 234 East Gish Road San Jose, CA USA Tel: (408) Fax: (408)