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Date: Fri, 18 Jun 2010 10:40:02 +0900 From: Minchan Kim <minchan.kim@...il.com> To: Tim Chen <tim.c.chen@...ux.intel.com> Cc: Andrew Morton <akpm@...ux-foundation.org>, linux-kernel@...r.kernel.org, Andi Kleen <ak@...ux.intel.com>, Hugh Dickins <hughd@...gle.com>, yanmin.zhang@...el.com Subject: Re: [PATCH v3 0/2] tmpfs: Improve tmpfs scalability On Fri, Jun 18, 2010 at 8:56 AM, Tim Chen <tim.c.chen@...ux.intel.com> wrote: > This patch series helps to resolve scalability problem > for tmpfs. With these patches, Aim7 fserver throughput for tmpfs > improved by 270% on a 4 socket, 32 cores NHM-EX system. > > In current implementation of tmpfs, whenever we > get a new page, stat_lock in shmem_sb_info needs to be acquired. > This causes a lot of lock contentions when multiple > threads are using tmpfs simultaneously, which makes > system with large number of cpus scale poorly. > Almost 75% of cpu time was spent contending on > stat_lock when we ran Aim7 fserver load with 128 threads > on a 4 socket, 32 cores NHM-EX system. > > We made use of the percpu_counter library for used blocks accounting to > speed up the getting and returning of blocks to local per cpu counter > without lock acquisition. > > The first patch in the series add a function to provide > fast but accurate comparison for the percpu_counter library. > > The second patch update the shmem code of tmpfs to use percpu_counter > library to improve tmpfs performance. > Patch series seems good to me. If you send a patch, please, make sure Cc list. tmpfs is related to mm. So when you send patch at next time, please Cc linux-mm. You can use ./script/get_maintainer.pl -f mm/shmem.c Thanks. -- Kind regards, Minchan Kim -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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