Messages in this thread | | | Subject | Re: 2.6.27-rc5 OLTP performance regression | From | Peter Zijlstra <> | Date | Mon, 08 Sep 2008 20:00:33 +0200 |
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On Mon, 2008-09-08 at 10:58 -0700, Ma, Chinang wrote: > We found the group scheduler in 2.6.27-rc5 has negative performance > impact on TPC Online Transaction Processing workload. The test was > conducted on a dual-socket quad-core Xeon server. OLTP workload is > disk i/o intensive and we have over 200 database shadow processes > running in the server during this test. Enabling group scheduler > (CONFIG_GROUP_SCHED=y) reduced performance by 2.0%. Oprofile data > indicates significant amount of cycles are spent in tg_shares_up(). > This is new regression as we did not find the same issue with 2.6.26 > kernel group scheduler. Is anybody looking into group scheduler > performance and any idea for reducing the performance impact?
Because the .26 group scheduler wasn't SMP aware. The extra cost comes from the fact that .27 is.
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