Messages in this thread | | | Subject | Re: load balancing regression since commit 367456c7 | From | Tim Chen <> | Date | Wed, 25 Apr 2012 10:58:46 -0700 |
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On Wed, 2012-04-25 at 19:43 +0200, Peter Zijlstra wrote: > Gargh.. lost the change to kernel/sched/features.h, now included. > > Sorry for that. > > --- > Subject: sched: Fix more load-balance fallout > From: Peter Zijlstra <a.p.zijlstra@chello.nl> > Date: Tue Apr 17 13:38:40 CEST 2012 > > Commits 367456c756a6 ("sched: Ditch per cgroup task lists for > load-balancing") and 5d6523ebd ("sched: Fix load-balance wreckage") > left some more wreckage. > > By setting loop_max unconditionally to ->nr_running load-balancing > could take a lot of time on very long runqueues (hackbench!). So keep > the sysctl as max limit of the amount of tasks we'll iterate. > > Furthermore, the min load filter for migration completely fails with > cgroups since inequality in per-cpu state can easily lead to such > small loads :/ > > Furthermore the change to add new tasks to the tail of the queue > instead of the head seems to have some effect.. not quite sure I > understand why. > > Combined these fixes solve the huge hackbench regression reported by > Tim when hackbench is ran in a cgroup. > > Reported-by: Tim Chen <tim.c.chen@linux.intel.com> > Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> > Link: http://lkml.kernel.org/r/1335365763.28150.267.camel@twins
The patch fixed the regression for me.
Acked-by: Tim Chen <tim.c.chen@linux.intel.com>
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