On Mon, Mar 17, 2003 at 02:05:06PM -0800, Andrew Morton wrote:
> Alex Tomas <bzzz@tmi.comex.ru> wrote:
> >
> > w> You should ask Andrew about his patch to do exactly that: he
> > w> forced all PROC_EXEC mmaps to be nonlinear-mapped and this forced
> > w> all programs to suck entire binaries into memory... I recall he
> > w> saw at least 25% improvement at launching gnome.
> >
> > they talked about pages _already present_ in pagecache.
>
> 2.5.64-mm8 does that too. At mmap-time it will, for a PROT_EXEC mapping,
> pull every affected page off disk and it will instantiate pte's against
> them all via install_page().
>
> So there should be zero major and minor faults against that mmap region
> during application startup.
>
> The improved IO layout appears to halve startup time for big things. I
> haven't attempted to instrument the effects of the reduced minor fault rate.
> If indeed the rate _has_ decreased. If it hasn't, it's a bug...
>
>
>
> This is all a bit dubious for several reasons. Most particularly, the
> up-front instantiation of the pages in pagetables makes unneeded pages harder
> to reclaim. It would be really neat if someone could try putting the
> madvise(MADV_WILLNEED) into glibc and test that. Maybe on a 2.4 kernel.
something like this one?
This archive was generated by hypermail 2b29 : Sun Mar 23 2003 - 22:00:21 EST