Re: 20% performance drop on PostgreSQL 9.2 from kernel 3.5.3 to 3.6-rc5 on AMD chipsets - bisected

Borislav Petkov
2012-09-28T12:29:47Z

On Fri, Sep 28, 2012 at 05:50:20AM +0200, Mike Galbraith wrote:
> And wakeup preemption is still disabled as well, correct?

Yes it is by default anyway:

$ cat /mnt/dbg/sched_features
GENTLE_FAIR_SLEEPERS START_DEBIT NO_NEXT_BUDDY LAST_BUDDY CACHE_HOT_BUDDY NO_WAKEUP_PREEMPTION ARCH_POWER NO_HRTICK NO_DOUBLE_TICK LB_BIAS OWNER_SPIN NONTASK_POWER TTWU_QUEUE NO_FORCE_SD_OVERLAP RT_RUNTIME_SHARE NO_LB_MIN

NO_WAKEUP_PREEMPTION brings 9% improvement with pgbench, btw:

http://marc.info/?l=linux-kernel&m=134876312310048

--
Regards/Gruss,
Boris.