Messages in this thread | | | Date | Tue, 29 Apr 2008 20:22:58 +0530 | From | "Balbir Singh" <> | Subject | Re: Page Faults slower in 2.6.25-rc9 than 2.6.23 |
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On Tue, Apr 29, 2008 at 7:27 PM, Hugh Dickins <hugh@veritas.com> wrote: > On Tue, 29 Apr 2008, Ross Biro wrote: > > I don't know if this has been noticed before. I was benchmarking my > > page table relocation code and I noticed that on 2.6.25-rc9 page > > faults take 10% more time than on 2.6.22. This is using lmbench > > running on an intel x86_64 system. The good news is that the page > > table relocation code now only adds a 1.6% slow down to page faults. > > Do you have CONFIG_CGROUP_MEM_RES_CTLR=y in 2.6.25? > That added about 20% to my lmbench "Page Fault" tests (with > adverse effect on several others e.g. the fork, exec, sh group). >
Hmm.. strange.. I don't remember the overhead being so bad (I'll relook at my old numbers). I'll try and git-bisect this one
> Try the same kernel with boot option "cgroup_disable=memory", > that should recoup most (but not quite all) of the slowdown; > or rebuild with n to CGROUP_MEM_RES_CTLR. > > But your "Mmap Latency" went up 425% ?? >
That's really way of the mark
> Hugh >
Balbir
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