Messages in this thread | | | From | urbanski@us ... | Date | Sat, 30 Jan 1999 23:29:26 -0700 | Subject | 2.2.1 SMP Scalability to 4-way |
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OK this is a long story but I'll try to be brief. We were asked to benchmark a computational chemistry application for a major drug company on a 4-way Xeon machine. They wanted Unix, and the only two supported on X86 were Solaris and Linux. The SMP performance of the 2.0.x kernels was poor, so we were forced to bid Solaris on this one - shame because it would have been a good reference - they need 36 4-way Xeon machines to meet their computational requirements.
But in any case I wanted to try Linux again when 2.2 came out - so I just re-ran the numbers. It's decidedly a good-news, bad news case. Here they are (times are in seconds)
Linux 512M RAM Scalability (from 1X)
1 CPU = 1503 - 2 CPU = 702 107% 3 CPU = 494 101.4% 4 CPU = 954 39%
Solaris 512M RAM
1 CPU = 1029 - 2 CPU = 588 87.5% 3 CPU = 447 76.7% 4 CPU = 411 62.6%
Linux scales much better up to 3 CPU's - so much so that we almost caught up at the end - in fact we might have because the Solaris machine is using 1M cache CPU's compared to the 512K on the Linux box. I'll do an apples-to-apples comparison tomorrow. But there is obviously somthing wrong when I go to 4 CPUs - it takes longer than 3, or even 2! This is discouraging because I have several other opportunities but I can't recommend Linux for them until I know it can scale reliably. If anyone can help me troubleshoot this please copy me via email.
Jay Urbanski Netfinity Systems Engineer IBM Advanced Technical Support MCSE, PSE, Certified Solaris Systems Administrator (817)962-3597 TL 522-3597 (817)962-7307 fax (800)413-9093 pager urbanski@us.ibm.com
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