From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755499AbYHKVed (ORCPT ); Mon, 11 Aug 2008 17:34:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751878AbYHKVeV (ORCPT ); Mon, 11 Aug 2008 17:34:21 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:33802 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754882AbYHKVeT (ORCPT ); Mon, 11 Aug 2008 17:34:19 -0400 Message-ID: <48A0B037.501@linux-foundation.org> Date: Mon, 11 Aug 2008 16:33:43 -0500 From: Christoph Lameter User-Agent: Thunderbird 2.0.0.16 (Windows/20080708) MIME-Version: 1.0 To: David Miller CC: netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: tbench regression on each kernel release from 2.6.22 -> 2.6.28 References: <48A086B6.2000901@linux-foundation.org> <20080811.141501.01468546.davem@davemloft.net> In-Reply-To: <20080811.141501.01468546.davem@davemloft.net> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org David Miller wrote: > Isn't that when some major scheduler changes went in? I'm not blaming > the scheduler, but rather I'm making the point that there are other > subsystems in the kernel that the networking interacts with that > influences performance at such a low level. This includes the memory > allocator :-) Right this covers a significant portion of the kernel. SLAB was used since .22 was pretty early for SLUB. And around 2.6.24 we had the merges of the antifrag logic. .25 was the point where HR timers came in. By switching off hrtimers I can get some (minor) portion of performance back. There must be more things in play though. Maybe what we are seeing is general bloat in kernel execution paths due to the growth in complexity?