Messages in this thread | | | Subject | Re: hackbench [pthread mode] regression with 2.6.29-rc3 | From | Peter Zijlstra <> | Date | Sun, 01 Feb 2009 10:17:16 +0100 |
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On Sun, 2009-02-01 at 16:29 +0800, Lin Ming wrote: > > Bisect located below patch. > > commit 490dea45d00f01847ebebd007685d564aaf2cd98 > > Author: Peter Zijlstra <peterz@infradead.org> > > Date: Mon Nov 24 17:06:57 2008 +0100 > > > > itimers: remove the per-cpu-ish-ness > > > > Either we bounce once cacheline per cpu per tick, yielding n^2 bounces > > or we just bounce a single.. > > > > Also, using per-cpu allocations for the thread-groups complicates the > > per-cpu allocator in that its currently aimed to be a fixed sized > > allocator and the only possible extention to that would be vmap based, > > which is seriously constrained on 32 bit archs. > > > > > > After above patch is reverted, hackbench result is restored. > > oltp has ~3% regression with 2.6.29-rc3 on 4core*2p stokley machine. > After above patch reverted, the regression disappeared.
*sigh*, did they gain anything with introduction of the per-cpu crap?
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