Messages in this thread | | | Date | Sat, 21 Apr 2007 02:48:25 +0200 | From | Eric Dumazet <> | Subject | Re: [PATCH] lazy freeing of memory through MADV_FREE |
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Rik van Riel a écrit : > Andrew Morton wrote: >> On Fri, 20 Apr 2007 17:38:06 -0400 >> Rik van Riel <riel@redhat.com> wrote: >> >>> Andrew Morton wrote: >>> >>>> I've also merged Nick's "mm: madvise avoid exclusive mmap_sem". >>>> >>>> - Nick's patch also will help this problem. It could be that your >>>> patch >>>> no longer offers a 2x speedup when combined with Nick's patch. >>>> >>>> It could well be that the combination of the two is even better, >>>> but it >>>> would be nice to firm that up a bit. >>> I'll test that. >> >> Thanks. > > Well, good news. > > It turns out that Nick's patch does not improve peak > performance much, but it does prevent the decline when > running with 16 threads on my quad core CPU! > > We _definately_ want both patches, there's a huge benefit > in having them both. > > Here are the transactions/seconds for each combination: > > vanilla new glibc madv_free kernel madv_free + mmap_sem > threads > > 1 610 609 596 545
545 tps versus 610 tps for one thread ? It seems quite bad, no ?
Could you please find an explanation for this ?
> 2 1032 1136 1196 1200 > 4 1070 1128 2014 2024 > 8 1000 1088 1665 2087 > 16 779 1073 1310 1999 > >
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