[lkml]   [2009]   [Mar]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: [PATCH 00/35] Cleanup and optimise the page allocator V3
    On Mon, Mar 16, 2009 at 12:11:22PM +0000, Mel Gorman wrote:
    > On Mon, Mar 16, 2009 at 12:45:55PM +0100, Nick Piggin wrote:
    > > On Mon, Mar 16, 2009 at 09:45:55AM +0000, Mel Gorman wrote:
    > > > Here is V3 of an attempt to cleanup and optimise the page allocator and should
    > > > be ready for general testing. The page allocator is now faster (16%
    > > > reduced time overall for kernbench on one machine) and it has a smaller cache
    > > > footprint (16.5% less L1 cache misses and 19.5% less L2 cache misses for
    > > > kernbench on one machine). The text footprint has unfortunately increased,
    > > > largely due to the introduction of a form of lazy buddy merging mechanism
    > > > that avoids cache misses by postponing buddy merging until a high-order
    > > > allocation needs it.
    > >
    > > BTW. I would feel better about this if it gets merged in stages, with
    > > functional changes split out, and also code optimisations and omore
    > > obvious performace improvements split out and preferably merged first.
    > >
    > The ordering of the patches was such that least-controversial stuff is
    > at the start of the patchset. The intention was to be able to select a
    > cut-off point and say "that's enough for now"
    > > At a very quick glance, the first 25 or so patches should go in first,
    > > and that gives a much better base to compare subsequent functional
    > > changes with.
    > That's reasonable. I've requeued tests for the patchset up to 25 to see what
    > that looks like. There is also a part of a later patch that reduces how much
    > time is spent with interrupts disabled. I should split that out and move it
    > back to within the cut-off point as something that is "obviously good".

    OK cool. It also means we can start getting benefit of some of them
    sooner. I hope most of the obvious ones can be merged in 2.6.30.

    > > Patch 18 for example is really significant, and should
    > > almost be 2.6.29/-stable material IMO.
    > >
    > My impression was that -stable was only for functional regressions where
    > as this is really a performance thing.

    A performance regression like this in the core page allocator is a
    pretty important problem. The fix is obvious. But maybe you're right.

     \ /
      Last update: 2009-03-16 13:31    [W:0.022 / U:9.680 seconds]
    ©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site