Date: Wed, 5 Dec 2012 17:41:48 -0500
From: Bruce Momjian <bruce@momjian.us>
To: Shaun Thomas <sthomas@optionshouse.com>
Cc: Daniel Farina <daniel@heroku.com>,
	"pgsql-performance@postgresql.org" <pgsql-performance@postgresql.org>
Subject: Re: Ubuntu 12.04 / 3.2 Kernel Bad for PostgreSQL
 Performance
Message-ID: <20121205224148.GC30887@momjian.us>
References: <50BF9247.2010800@optionshouse.com>
	<CAAZKuFauzW3W4FmvGLZo_+8taY5Gk_6PeLQqZ3kE6M7D0XrJRw@mail.gmail.com>
	<50BFC9D8.4010507@optionshouse.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <50BFC9D8.4010507@optionshouse.com>
User-Agent: Mutt/1.5.20 (2009-06-14)
Precedence: bulk
Sender: pgsql-performance-owner@postgresql.org

On Wed, Dec  5, 2012 at 04:25:28PM -0600, Shaun Thomas wrote:
> On 12/05/2012 04:19 PM, Daniel Farina wrote:
> 
> >Is 3.2 a significant regression from previous releases, or is 3.4 just
> >faster?  Your wording only indicates that "older kernel is slow," but
> >your tone would suggest that you feel this is a regression, cf.
> 
> It's definitely a regression. I'm trying to pin it down, but the
> 3.2.0-24 kernel didn't do the CPU drain down to single-digits on
> that client load test. I'm working on 3.2.0-30 and going down to
> figure out which patch might have done it.
> 
> Older kernels performed better. And by older, I mean 2.6. Still not
> 3.4 levels, but that's expected. I haven't checked 3.0, but other
> threads I've read suggest it had less problems. Sorry if I wasn't
> clear.

Ah, that is interesting about 2.6.  I had wondered how Debian stable
would have performed, 2.6.32-5.  This relates to a recent discussion
about the appropriateness of Ubuntu for database servers:

	http://archives.postgresql.org/pgsql-performance/2012-11/msg00358.php

Thanks.

-- 
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

  + It's impossible for everything to be true. +


-- 
Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-performance