[lkml]   [2002]   [Oct]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: [patch] mmap-speedup-2.5.42-C3
    On Wed, Oct 16, 2002 at 10:03:52AM +0200, Ingo Molnar wrote:
    > On 15 Oct 2002, Andi Kleen wrote:
    > > When you oprofile KDE startup you notice that a lot of time is spent in
    > > get_unmapped_area too. The reason is that every KDE process links with
    > > 10-20 libraries and ends up with a 40-50 entry /proc/<pid>/maps.
    > actually, library mappings alone should not cause a slowdown, since we
    > start the search at MAP_UNMAPPED_BASE and most library mappings are below
    > 1GB. But if those libraries use mmap()-ed anonymous RAM that has different
    > protections then the anonymous areas do not get merged and the scanning
    > overhead goes up.

    Libraries mapped by dynamic linker are mapped without MAP_FIXED and unless
    you use prelinking, with 0 virtual address, ie. they all end up above 1GB.
    And 99% of libraries uses different protections, for the read-only and
    read-write segment.

    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to
    More majordomo info at
    Please read the FAQ at

     \ /
      Last update: 2005-03-22 13:30    [W:0.018 / U:130.612 seconds]
    ©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site