System News
SPECpower Issues in the SPECpower_ssj2008 of Sun Netra X4250 and the Competition
The Effect of Utilization Rate on Power Consumption
June 19, 2009,
Volume 136, Issue 3

A look at SPECpower issues

In SPECpower_ssj2008 Sun Netra X4250 - SPECpower issues highlighted, BM Seer writes that the Sun Netra X4250 8GB server (two 2.13 GHz Intel L5408 QC) obtained a peak overall ssj_ops/watt metric of 600 (with special BIOS tuning). A more typical 32GB configuration of the same system achieved results of 478 (with special BIOS tuning) and a lower 437 (with standard BIOS settings).

These results were obtained on the Sun Netra X4250 server using Microsoft Windows Server 2003 R2 Enterprise x64 Edition SP2 and Sun Java HotSpot 32-Bit Server VM on Windows, version 1.6.0_14, Seer continues, adding that SPECpower_ssj results show that servers (even those with the industry's best power-management) running at low-utilization levels use many times more watts per unit-of-work than systems running at higher utilization levels. Datacenters can realize the biggest energy savings by running fewer servers at higher utilization levels (50% utilization or above).

Sun's results on the 8GB (or 0.5GB/core) configuration show that running at 10% utilization requires 4.4 times more power per unit of work than running at 50% utilization. 4.4 times = (581 performance-to-power @ 50% utilization /133 performance-to-power @ 10% utilization), he writes.

Most SPECpower_ssj2008 are published on small-memory configurations that are much smaller than typical customer deployments. Sun is the only vendor to publish multiple results to clearly show effect of memory configuration, Seer notes.

He further reports that a more normal-sized memory configuration of 32GB (or 2GB/core) uses 30% more watts than a tiny 8GB (or 0.5GB/core) configuration at 100% load. At active-idle the wattage difference is also 30%. Some competitors use additional configuration differences such as non-redundant fans, non-redundant power supplies, and single slow disk to further reduce the wattages and significantly improve SPECpower_ssj scores.

While most published SPECpower_ssj2008 results make low-level BIOS changes to turn off hardware prefetch, Sun shows that non-default BIOS changes improve Peak Performance ssj_ops by 9%. This non-default BIOS change hurts the performance of other workloads, Seer observes.

All three of Sun's servers under test (Sun Netra X4250: 8GB non-standard BIOS; 32GB non-standard BIOS; 32GB default BIOS) used the same software components and processors: Processor: 2 x Intel L5408 QC 2.13 GHz; Operating System: Windows Server 2003 R2 Enterprise x64 Edition SP2; JVM: java HotSpot(TM) 32-Bit Server VM on Windows, version 1.6.0_14. Results for the Sun Netra X4250 Server came in at the bottom of the field, following the Powerleader PR2510D2, the NEC ECO CENTER; the HP Proliant DL180 G5; the Fujitsu PRIMERGY TX 300 S4; and the Dell PowerEdge R300.

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Sun Netra X4250

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Other articles in the Performance section of Volume 136, Issue 3:
  • SPECpower Issues in the SPECpower_ssj2008 of Sun Netra X4250 and the Competition (this article)

See all archived articles in the Performance section.

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