Re: [Lse-tech] [patch] sched-domain cleanups, sched-2.6.5-rc2-mm2-A3

Ingo Molnar
2004-03-25T19:09:24Z

* Andi Kleen <ak@suse.de> wrote:

> It doesn't do load balance in wake_up_forked_process() and is
> relatively non aggressive in balancing later. This leads to the
> multithreaded OpenMP STREAM running its childs first on the same node
> as the original process and allocating memory there. [...]

i believe the fix we want is to pre-balance the context at fork() time.
I've implemented this (which is basically just a reuse of
sched_balance_exec() in fork.c, and the related namespace cleanups),
could you give it a go:

http://redhat.com/~mingo/scheduler-patches/sched-2.6.5-rc2-mm2-A5

another solution would be to add SD_BALANCE_FORK.

also, the best place to do fork() blancing is not at
wake_up_forked_process() time, but prior doing the MM copy. This patch
does it there. At wakeup time we've already copied all the pagetables
and created tons of dirty cachelines.

Ingo