Messages in this thread | | | Subject | Re: volanoMark regression with kernel 2.6.26-rc1 | From | Peter Zijlstra <> | Date | Thu, 15 May 2008 10:41:38 +0200 |
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On Thu, 2008-05-15 at 13:50 +0530, Srivatsa Vaddagiri wrote: > On Wed, May 14, 2008 at 05:12:47PM +0200, Peter Zijlstra wrote: > > A few other things I found that make a significant difference: > > One more observation: access to aggregate()->rq_weight etc arent > correctly synchronized i.e while a cpu is doing a aggregate_walk_tree() > in a domain, and thus possibly modifying rq_weight, load etc, other cpus could > be concurrently accessing the same data. As a result, its possible to > see inconsistent rq_weight, load, task_weight combination?
Yes - and that should not be too big an issue as long as we can deal with it.
Any number we'll put to it will be based on a snapshot of the state so we're wrong no matter what we do. The trick is trying to keep sane.
My current stack on top of sched-devel:
http://programming.kicks-ass.net/kernel-patches/sched-smp-group-fixes/
I've found that: http://programming.kicks-ass.net/kernel-patches/sched-smp-group-fixes/sched-agg-update-move_tasks.patch
was sufficient to deal with all the anomalities I've found so far.
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