Re: 20% performance drop on PostgreSQL 9.2 from kernel 3.5.3 to3.6-rc5 on AMD chipsets - bisected

From: Peter Zijlstra
Date: Mon Sep 24 2012 - 12:07:58 EST


On Mon, 2012-09-24 at 08:52 -0700, Linus Torvalds wrote:
> Your patch looks odd, though. Why do you use some complex initial
> value for 'candidate' (nr_cpu_ids) instead of a simple and readable
> one (-1)?

nr_cpu_ids is the typical no-value value for cpumask operations -- yes
this is annoying and I keep doing it wrong far too often.
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