Messages in this thread | | | Subject | Re: Scheduler(?) regression from 2.6.22 to 2.6.24 for short-lived threads | From | Mike Galbraith <> | Date | Sat, 09 Feb 2008 08:58:39 +0100 |
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On Fri, 2008-02-08 at 18:04 -0600, Olof Johansson wrote: > Hi, > > I ended up with a customer benchmark in my lap this week that doesn't > do well on recent kernels. :( > > After cutting it down to a simple testcase/microbenchmark, it seems like > recent kernels don't do as well with short-lived threads competing > with the thread it's cloned off of. The CFS scheduler changes come to > mind, but I suppose it could be caused by something else as well. > > The pared-down testcase is included below. Reported runtime for the > testcase has increased almost 3x between 2.6.22 and 2.6.24: > > 2.6.22: 3332 ms > 2.6.23: 4397 ms > 2.6.24: 8953 ms > 2.6.24-git19: 8986 ms
My 3GHz P4 shows disjointed results.
2.6.22.17-smp time 798 ms time 780 ms time 702 ms
2.6.22.17-cfs-v24.1-smp time 562 ms time 551 ms time 551 ms
2.6.23.15-smp time 254 ms time 254 ms time 293 ms
2.6.23.15-cfs-v24-smp time 764 ms time 791 ms time 780 ms
2.6.24.1-smp time 815 ms time 820 ms time 771 ms
2.6.25-smp (git today) time 29 ms time 61 ms time 72 ms
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