Re: 20% performance drop on PostgreSQL 9.2 from kernel 3.5.3 to3.6-rc5 on AMD chipsets - bisected
From: Alan Cox
Date: Sat Sep 15 2012 - 17:28:17 EST
> Yes, postgress performs loads better with it's spinlocks, but due to
> that, it necessarily _hates_ preemption. How the is the scheduler
> supposed to know that any specific userland task _really_ shouldn't be
> preempted at any specific time, else bad things follow?
You provide a shared page for a process group so it can write hints to
which is kernel mapped so the scheduler can peek..
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