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

On 09/14/2012 10:45 AM, Daniel Farina wrote:
> On Fri, Sep 14, 2012 at 12:40 AM, Nikolay Ulyanitsky <lystor(at)gmail(dot)com> wrote:
>> Hi
>> I compiled the 3.6-rc5 kernel with the same config from 3.5.3 and got
>> the 15-20% performance drop of PostgreSQL 9.2 on AMD chipsets (880G,
>> 990X).

[cut]

>> Kernel config - http://pastebin.com/cFpg5JSJ
>>
>> Any ideas?
>
> Did you tell LKML? It seems like a kind of change that could be found
> using git bisect of Linux, albiet laboriously.

just a pointer to LKML thread:

https://lkml.org/lkml/2012/9/14/99

it seems that kernel dev were able to find the root cause
after bisecting kernel source.

Borislav Petkov says that regression disappears
after reverting this commit:

commit 970e178985cadbca660feb02f4d2ee3a09f7fdda
Author: Mike Galbraith <efault(at)gmx(dot)de>
Date: Tue Jun 12 05:18:32 2012 +0200

Andrea