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

From: Linus Torvalds
Date: Mon Sep 24 2012 - 15:12:42 EST


On Mon, Sep 24, 2012 at 11:26 AM, Mike Galbraith <efault@xxxxxx> wrote:
>
> Aside from the cache pollution I recall having been mentioned, on my
> E5620, cross core is a tbench win over affine, cross thread is not.

Oh, I agree with trying to avoid HT threads, the resource contention
easily gets too bad.

It's more a question of "if we have real cores with separate L1's but
shared L2's, go with those first, before we start distributing it out
to separate L2's".

Linus
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