LRDIMM - Powers up Transaction Processing - Inphi Corporation

More documents

Recommendations

Info

The results discussed above reflect the speed advantage of LRDIMM over RDIMM for systems with equal amounts of DRAM installed, 512GB in this case, with LRDIMM running at 1333 MT/s compared to 1066 MT/s for RDIMM. For benchmarks like TPC-E, and real-world applications where the database size is significantly larger than the installed memory, LRDIMM would provide an additional performance advantage by allowing a higher amount of memory to be installed at the same operational frequency, reducing the required hard disk access time by resolving more database queries in DRAM. The TPC-E benchmark also rates the server systems tested based on cost (in US dollars) per transaction per second, or $/tpsE. By this metric, the LRDIMM system fared very well, ranking as the 8th lowest in $/tpsE out of 55 different systems reported on the TPC website even using IBM’s list price of $4,599 at the time of the test. However, the price of 32GB LRDIMM is coming down quickly. For example, IBM is now listing the 32GB LRDIMM for $2,099. Using this price, the $/tpsE is approximately $196 thereby significantly improving the cost efficiency of the overall server as shown in Table 2. LRDIMM Overview Table 2: USD $/tpsE The LRDIMM enables the performance improvement observed in these TPC-E benchmark results by isolating multiple ranks of DRAM behind a memory buffer such as Inphi’s iMB02-GS02A, as shown in Figure 3. In a traditional RDIMM module the data bus signals from the host connect through the DIMM connector directly to the DRAM, placing multiple DRAM loads on every data bit for multi-rank modules, including the DRAM loads from adjacent RDIMM modules in the same memory channel. If four-rank RDIMMs are installed in a channel with two DIMM slots, each data bit would see eight electrical loads, limiting signal integrity and system performance at higher speeds. In an LRDIMM module the data bus signals from the host connect through the DIMM connector to the memory buffer, which re-drives the data bus to the DRAM on the front and back sides of the module. The memory buffer thus isolates the DRAM from the host, and from the DRAM on any adjacent LRDIMM module on the same memory channel. For a system with two DIMM slots per channel, the memory controller would see two electrical loads (the memory buffer on each LRDIMM), compared to eight electrical loads in an RDIMM system (the four ranks of DRAM on each RDIMM). This load reduction enables the memory data bus to operate at higher speeds with no loss of signal integrity, providing system performance benefits in memory intensive applications such as online transaction processing. The LRDIMM’s memory buffer also buffers the command, address and control signals from the memory controller, similar to the way that the register on an RDIMM buffers those signals. In systems with three DIMM slots per channel the memory buffer enables additional increases in memory capacity, overcoming the traditional limit of eight chip selects per channel through a feature called Rank Multiplication, allowing the use of three four-rank LRDIMM modules in a single channel. Eight-rank LRDIMMs are also possible, with several module vendors having announced 64GB 8Rx4 LRDIMMs. Figure 3: LRDIMM LRDIMM Powers up Transaction Processing 4
Conclusion DDR3 LRDIMM memory provides significant performance improvement over traditional DDR3 RDIMM memory by enabling higher memory access speeds for a given memory capacity, or by allowing higher memory capacities at a given memory speed. IBM has published TPC-E benchmark results confirming this dramatic performance improvement with LRDIMM using Inphi’s iMB02-GS02A Isolation Memory Buffer. The published results show the cost effectiveness of LRDIMM as a commercially available DRAM solution, one which will become even more cost effective over time. The TPC-E benchmark models real world brokerage house functions with large customer databases, showing the promise of LRDIMM in powering up online transaction processing and all time-critical, memory-intensive processing tasks. Sources TPC Benchmark E Full Disclosure Report for IBM® System x® 3650 M4 using Microsoft® SQL Server 2012 Enterprise Edition and Microsoft Windows® Server 2008 R2 Enterprise Edition SP1, March 6, 2012, published online at http://www.tpc.org/tpce/results/tpce_result_detail.aspid=112030601 TPC Benchmark E Full Disclosure Report for IBM® System x® 3690 X5 using Microsoft® SQL Server 2008 R2 Enterprise Edition and Microsoft Windows® Server 2008 R2 Enterprise Edition, May 27, 2011, published online at http://www.tpc.org/tpce/results/tpce_result_detail.aspid=111052701 All TPC-E results are posted on the website of the Transaction Processing Performance Council at http://www.tpc.org/tpce/results/tpce_results.asp Overview of TPC-E, published online at http://www.tpc.org/tpce/default.asp Key Benchmarks for Measuring Transaction Processing Performance, published online at http://searchdatamanagement.techtarget.com/feature/Key-benchmarks-for-measuring-transaction-processing-performance 10/26/2012 Inphi Headquarters 3945 Freedom Circle Suite 1100 Santa Clara, CA 95054 Phone: (408) 217-7300 Inphi Southern California 112 S. Lakeview Canyon Rd. Suite 100 Westlake Village, CA 91362 Phone: (805) 719-2300 Web: www.inphi.com © 2012 Inphi Corporation. All rights reserved. Inphi, the Inphi logo, Think fast, and ExacTik are registered trademarks of Inphi Corporation. iMB is a trademark of Inphi Corporation. 5
Page 1 and 2: LRDIMM - Powers up Transaction Proc
Page 3: The TPC-E benchmark driver generate

LRDIMM - Powers up Transaction Processing - Inphi Corporation

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?