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

Borislav Petkov
2012-09-27T18:04:47Z

On Thu, Sep 27, 2012 at 10:44:26AM -0700, Linus Torvalds wrote:
> Or could we just improve the heuristics. What happens if the
> scheduling granularity is increased, for example? It's set to 1ms
> right now, with a logarithmic scaling by number of cpus.

/proc/sys/kernel/sched_wakeup_granularity_ns=10000000 (10ms)
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tps = 4994.730809 (including connections establishing)
tps = 5000.260764 (excluding connections establishing)

A bit better over the default NO_WAKEUP_PREEMPTION setting.

--
Regards/Gruss,
Boris.