Messages in this thread | | | Subject | Re: [PATCH 10/15] sched: Check for sched_mn_power_savings when doing load balancing | From | Peter Zijlstra <> | Date | Mon, 24 Aug 2009 17:03:40 +0200 |
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On Thu, 2009-08-20 at 15:41 +0200, Andreas Herrmann wrote: > The patch adds support for POWERSAVINGS_BALANCE_BASIC for MN domain > level. Currently POWERSAVINGS_BALANCE_WAKEUP is not used for MN domain. > > (I have to admit that so far I don't have the correct understanding > what's the benefit of POWERSAVINGS_BALANCE_WAKEUP (when an deticated > wakeup CPU is used) in contrast to POWERSAVINGS_BALANCE_BASIC. I also > have not found an example that would demonstrate the difference > between those two powersaving levels.)
blame svaidy for not writing enough comments ;-)
iirc it moves tasks to sched_mv_preferred_wakeup_cpu instead of waking an idle cpu, this leaves idle cpus idle longer at the cost of creating overload on other cpus.
> Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com> > --- > kernel/sched.c | 5 +++-- > 1 files changed, 3 insertions(+), 2 deletions(-) > > diff --git a/kernel/sched.c b/kernel/sched.c > index ebcda58..7a0d710 100644 > --- a/kernel/sched.c > +++ b/kernel/sched.c > @@ -4591,7 +4591,8 @@ static int find_new_ilb(int cpu) > * Have idle load balancer selection from semi-idle packages only > * when power-aware load balancing is enabled > */ > - if (!(sched_smt_power_savings || sched_mc_power_savings)) > + if (!(sched_smt_power_savings || sched_mc_power_savings || > + sched_mn_power_savings)) > goto out_done; > > /* > @@ -4681,7 +4682,7 @@ int select_nohz_load_balancer(int stop_tick) > int new_ilb; > > if (!(sched_smt_power_savings || > - sched_mc_power_savings)) > + sched_mc_power_savings || sched_mn_power_savings)) > return 1; > /* > * Check to see if there is a more power-efficient
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