Received: from localhost (unknown [200.46.204.187]) by postgresql.org (Postfix) with ESMTP id 523682E2D7C for ; Mon, 26 Nov 2007 19:41:47 -0400 (AST) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.187]) (amavisd-maia, port 10024) with ESMTP id 30963-08 for ; Mon, 26 Nov 2007 19:41:24 -0400 (AST) Received: from cbc.xplorcapital.com (unknown [63.101.201.81]) by postgresql.org (Postfix) with ESMTP id E94952E034F for ; Mon, 26 Nov 2007 19:41:40 -0400 (AST) Received: from [192.168.2.25] (xw1.bbd [192.168.2.25]) by cbc.xplorcapital.com (Postfix) with ESMTP id C971D5A008; Mon, 26 Nov 2007 18:41:39 -0500 (EST) Subject: Re: PostgreSQL performance on various distribution stock kernels From: Damon Hart To: Tom Lane Cc: pgsql-performance@postgresql.org In-Reply-To: <5104.1196118394@sss.pgh.pa.us> References: <1196117408.19996.16.camel@xw1.bbd> <5104.1196118394@sss.pgh.pa.us> Content-Type: text/plain Date: Mon, 26 Nov 2007 18:41:39 -0500 Message-Id: <1196120499.19996.44.camel@xw1.bbd> Mime-Version: 1.0 X-Mailer: Evolution 2.8.3 (2.8.3-2.fc6) Content-Transfer-Encoding: 7bit X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200711/313 X-Sequence-Number: 27728 On Mon, 2007-11-26 at 18:06 -0500, Tom Lane wrote: > Damon Hart writes: > > So, what's different between these tests? I'm seeing performance > > differences of between +65% to +90% transactions per second of the > > OpenVZ kernel running on the HN over the stock Fedora 8 kernel. Is > > this reflective of different emphasis between RHEL and Fedora kernel > > builds? Some OpenVZ optimization on top of the RHEL5 build? Something > > else? Where should I look? > > Considering how raw Fedora 8 is, I think what you've probably found is a > performance bug that should be reported to the kernel hackers. > Not being a kernel hacker, any suggestions on how to provide more useful feedback than just pgbench TPS comparison and hardware specs? What's the best forum, presuming this does boil down to kernel issues. > Just to confirm: this *is* the same filesystem in both cases, right? > > regards, tom lane Yes, same filesystem simply booting different kernels. Damon