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    SubjectRe: [PATCH] MM: implement MADV_FREE lazy freeing of anonymous memory
    Rik van Riel wrote:
    > Nick Piggin wrote:
    >> Rik van Riel wrote:
    >>> With lazy freeing of anonymous pages through MADV_FREE, performance of
    >>> the MySQL sysbench workload more than doubles on my quad-core system.
    >> OK, I've run some tests on a 16 core Opteron system, both sysbench with
    >> MySQL 5.33 (set up as described in the freebsd vs linux page), and with
    >> ebizzy.
    >> What I found is that, on this system, MADV_FREE performance improvement
    >> was in the noise when you look at it on top of the MADV_DONTNEED glibc
    >> and down_read(mmap_sem) patch in sysbench.
    > Interesting, very different results from my system.
    > First, did you run with the properly TLB batched version of
    > the MADV_FREE patch? And did you make sure that MADV_FREE
    > takes the mmap_sem for reading? Without that, I did see
    > a similar thing to what you saw...

    Yes and yes (I initially forgot to add MADV_FREE to the down_read
    case and saw horrible performance!)

    > Secondly, I'll have to try some test runs one of the larger
    > systems in the lab.
    > Maybe the results from my quad core Intel system are not
    > typical; maybe the results from your 16 core Opteron are
    > not typical. Either way, I want to find out :)

    Yep. We might have something like that here, and I'll try with
    some other architectures as well next week, if I can get glibc

    SUSE Labs, Novell Inc.
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      Last update: 2007-05-05 01:53    [W:0.157 / U:0.564 seconds]
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