lkml.org 
[lkml]   [2011]   [Dec]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    SubjectRe: [PATCH 1/3] slub: set a criteria for slub node partial adding
    From
    Date
    On Fri, 2011-12-02 at 19:36 +0800, Eric Dumazet wrote:
    > Le vendredi 02 décembre 2011 à 16:23 +0800, Alex Shi a écrit :
    > > From: Alex Shi <alexs@intel.com>
    > >
    > > Times performance regression were due to slub add to node partial head
    > > or tail. That inspired me to do tunning on the node partial adding, to
    > > set a criteria for head or tail position selection when do partial
    > > adding.
    > > My experiment show, when used objects is less than 1/4 total objects
    > > of slub performance will get about 1.5% improvement on netperf loopback
    > > testing with 2048 clients, wherever on our 4 or 2 sockets platforms,
    > > includes sandbridge or core2.
    > >
    > > Signed-off-by: Alex Shi <alex.shi@intel.com>
    > > ---
    > > mm/slub.c | 18 ++++++++----------
    > > 1 files changed, 8 insertions(+), 10 deletions(-)
    > >
    >
    > netperf (loopback or ethernet) is a known stress test for slub, and your
    > patch removes code that might hurt netperf, but benefit real workload.
    >
    > Have you tried instead this far less intrusive solution ?
    >
    > if (tail == DEACTIVATE_TO_TAIL ||
    > page->inuse > page->objects / 4)
    > list_add_tail(&page->lru, &n->partial);
    > else
    > list_add(&page->lru, &n->partial);

    For loopback netperf, it has no clear performance change on all
    platforms.
    For hackbench testing, it has a bit worse on 2P NHM 0.5~1%, but it is
    helpful to increase about 2% on 4P(8cores * 2SMT) NHM machine.

    I was thought no much cache effect on hot or cold after per cpu partial
    adding. but seems for hackbench, node partial still has much effect.


    >
    >
    >


    --
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2011-12-05 04:33    [W:0.022 / U:0.552 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site