Messages in this thread | | | From | kamezawa.hiroyu@jp ... | Date | Thu, 11 Sep 2008 21:49:53 +0900 (JST) | Subject | Re: Re: [RFC] [PATCH 9/9] memcg: percpu page cgroup lookup cache |
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----- Original Message ----- >On Thursday 11 September 2008 21:24, KAMEZAWA Hiroyuki wrote: >> Use per-cpu cache for fast access to page_cgroup. >> This patch is for making fastpath faster. >> >> Because page_cgroup is accessed when the page is allocated/freed, >> we can assume several of continuous page_cgroup will be accessed soon. >> (If not interleaved on NUMA...but in such case, alloc/free itself is slow.) >> >> We cache some set of page_cgroup's base pointer on per-cpu area and >> use it when we hit. >> >> TODO: >> - memory/cpu hotplug support. > >How much does this help? > 1-2% in unixbench's test (in 0/9) on 2core/1socket x86-64/SMP host. (cpu is not the newest one.) This per-cpu covers 32 * 128MB=4GB of area. Using 256 bytes(32 entry) is over-kill ?
Thanks, -Kame
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