DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.co.uk;
	h=X-YMail-OSG:Received:X-Rocket-MIMEInfo:X-Mailer:References:Message-ID:Date:From:Reply-To:Subject:To:Cc:In-Reply-To:MIME-Version:Content-Type:Content-Transfer-Encoding;
	b=YFe66yT4z7JYdiJJhBthbJpFwpjEX23U5nvb18cfsZFXk8x0/0OGxwdHXwFnJ3Ggk0hXCZdwgeV3C9FrNLMeKMKPH9S+48X4RaHWnlr/3tvnC2fAzdUMYntfP97ebIJCUYoICwRrJwZWi1oveWGMC4hemaq55zH32rn0EkwK3pc=;
References: 
 <60B572D9298D944580F7D51195DD30804357FA4ABF@VMBX125.ihostexchange.net>
	<511BE879.8080706@agliodbs.com> <511C2F10.3080409@agliodbs.com>
	<60B572D9298D944580F7D51195DD30804357FA4DE2@VMBX125.ihostexchange.net>
	<511D2F11.6040706@agliodbs.com>
	<60B572D9298D944580F7D51195DD308043580CAA0B@VMBX125.ihostexchange.net>
	<511D79FE.7060705@agliodbs.com>
	<60B572D9298D944580F7D51195DD308043580CAA87@VMBX125.ihostexchange.net>
	<CAOR=d=3CqRL5jrFRTSg9kFdcJzKpx3TJSsoDwRqpPUO=ENoFRQ@mail.gmail.com>
	<511E7DC0.4090506@agliodbs.com>
	<CAOR=d=2cEi=ibGS4DCrFAWq8VtCz6XEYDsMyarBX=evshLWgKg@mail.gmail.com>
	<5122C507.7060303@agliodbs.com>
	<CAOR=d=3bXmMmTvh3cKCizhwsijxg6wh6ADC053w-dbkC3e_zCQ@mail.gmail.com>
	<5122FF50.8030903@catalyst.net.nz>
	<5123BB94.7030603@agliodbs.com> <512409AF.8010308@agliodbs.com>
	<CAOR=d=1u4vtxNX+xoMrX+-1G9DUu6QOZnLXu1moS2+XO1FX=WA@mail.gmail.com>
	<512551D2.9090407@agliodbs.com>
	<CAOR=d=1uh=MvS+fC0b-Q8ravmUwCz5301xZ4w3S-Y6gj8Hg71w@mail.gmail.com>
	<51259102.9040707@agliodbs.com>
Message-ID: <1361445861.94095.YahooMailNeo@web133206.mail.ir2.yahoo.com>
Date: Thu, 21 Feb 2013 11:24:21 +0000 (GMT)
From: Glyn Astill <glynastill@yahoo.co.uk>
Reply-To: Glyn Astill <glynastill@yahoo.co.uk>
Subject: Re: High CPU usage / load average after upgrading to Ubuntu 12.04
To: Josh Berkus <josh@agliodbs.com>, Scott Marlowe <scott.marlowe@gmail.com>
Cc: "pgsql-performance@postgresql.org" <pgsql-performance@postgresql.org>
In-Reply-To: <51259102.9040707@agliodbs.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1
Content-Transfer-Encoding: quoted-printable
Precedence: bulk
Sender: pgsql-performance-owner@postgresql.org

> From: Josh Berkus <josh@agliodbs.com>
>To: Scott Marlowe <scott.marlowe@gmail.com>=20
>Cc: pgsql-performance@postgresql.org=20
>Sent: Thursday, 21 February 2013, 3:14
>Subject: Re: [PERFORM] High CPU usage / load average after upgrading to Ub=
untu 12.04
>=20
>
>> Sounds to me like your IO system is stalling on fsyncs or something
>> like that.=A0 On machines with plenty of IO cranking up completion
>> target usuall smooths things out.=20
>
>It certainly seems like it does.=A0 However, I can't demonstrate the issue
>using any simpler tool than pgbench ... even running four test_fsyncs in
>parallel didn't show any issues, nor do standard FS testing tools.
>


I've missed a load of this thread and just scanned through what I can see, =
so apologies if I'm repeating anything.

If the suspicion is the IO system and you've tuned everything you can think=
 of; is there anything interesting in=A0meminfo/iostat/vmstat before/during=
 the stalls? If so can you cause anything similar via bonnie++ with the "-b=
" option?


--=20
Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-performance