Messages in this thread | | | Date | Thu, 25 Mar 2004 11:24:44 -0800 | From | "Martin J. Bligh" <> | Subject | Re: [Lse-tech] [patch] sched-domain cleanups, sched-2.6.5-rc2-mm2-A3 |
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>> 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.
How are you going to decide whether to rebalance at fork time or exec time? Exec time balancing is a *lot* more efficient, it just doesn't work for things that don't exec ... cloned threads would certainly be one case.
M.
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