Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754374AbZAOQsn (ORCPT ); Thu, 15 Jan 2009 11:48:43 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752814AbZAOQsb (ORCPT ); Thu, 15 Jan 2009 11:48:31 -0500 Received: from mga02.intel.com ([134.134.136.20]:45688 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751765AbZAOQsa convert rfc822-to-8bit (ORCPT ); Thu, 15 Jan 2009 11:48:30 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.37,270,1231142400"; d="scan'208";a="481958582" From: "Ma, Chinang" To: Matthew Wilcox , Andrew Morton CC: "Wilcox, Matthew R" , "linux-kernel@vger.kernel.org" , "Tripathi, Sharad C" , "arjan@linux.intel.com" , "Kleen, Andi" , "Siddha, Suresh B" , "Chilukuri, Harita" , "Styner, Douglas W" , "Wang, Peter Xihong" , "Nueckel, Hubert" , "chris.mason@oracle.com" , "srostedt@redhat.com" , "linux-scsi@vger.kernel.org" , Andrew Vasquez , Anirban Chakraborty Date: Thu, 15 Jan 2009 09:48:12 -0700 Subject: RE: Mainline kernel OLTP performance update Thread-Topic: Mainline kernel OLTP performance update Thread-Index: Acl2r8XsWrB1aSUFSqiW7cxXvJzbWQAfvg0A Message-ID: References: <20090114163557.11e097f2.akpm@linux-foundation.org> <20090115012147.GW29283@parisc-linux.org> In-Reply-To: <20090115012147.GW29283@parisc-linux.org> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3192 Lines: 76 >-----Original Message----- >From: Matthew Wilcox [mailto:matthew@wil.cx] >Sent: Wednesday, January 14, 2009 5:22 PM >To: Andrew Morton >Cc: Wilcox, Matthew R; Ma, Chinang; linux-kernel@vger.kernel.org; Tripathi, >Sharad C; arjan@linux.intel.com; Kleen, Andi; Siddha, Suresh B; Chilukuri, >Harita; Styner, Douglas W; Wang, Peter Xihong; Nueckel, Hubert; >chris.mason@oracle.com; srostedt@redhat.com; linux-scsi@vger.kernel.org; >Andrew Vasquez; Anirban Chakraborty >Subject: Re: Mainline kernel OLTP performance update > >On Wed, Jan 14, 2009 at 04:35:57PM -0800, Andrew Morton wrote: >> On Tue, 13 Jan 2009 15:44:17 -0700 >> "Wilcox, Matthew R" wrote: >> > >> >> (top-posting repaired. That @intel.com address is a bad influence ;)) > >Alas, that email address goes to an Outlook client. Not much to be done >about that. > >> (cc linux-scsi) >> >> > > This is latest 2.6.29-rc1 kernel OLTP performance result. Compare to >> > > 2.6.24.2 the regression is around 3.5%. >> > > >> > > Linux OLTP Performance summary >> > > Kernel# Speedup(x) Intr/s CtxSw/s us% sys% idle% >iowait% >> > > 2.6.24.2 1.000 21969 43425 76 24 0 0 >> > > 2.6.27.2 0.973 30402 43523 74 25 0 1 >> > > 2.6.29-rc1 0.965 30331 41970 74 26 0 0 > >> But the interrupt rate went through the roof. > >Yes. I forget why that was; I'll have to dig through my archives for >that. I took a quick look at the interrupts figure between 2.6.24 and 2.6.27. i/o interuputs is slightly down in 2.6.27 (due to reduce throughput). But both NMI and reschedule interrupt increased. Reschedule interrupts is 2x of 2.6.24. > >> A 3.5% slowdown in this workload is considered pretty serious, isn't it? > >Yes. Anything above 0.3% is statistically significant. 1% is a big >deal. The fact that we've lost 3.5% in the last year doesn't make >people happy. There's a few things we've identified that have a big >effect: > > - Per-partition statistics. Putting in a sysctl to stop doing them gets > some of that back, but not as much as taking them out (even when > the sysctl'd variable is in a __read_mostly section). We tried a > patch from Jens to speed up the search for a new partition, but it > had no effect. > > - The RT scheduler changes. They're better for some RT tasks, but not > the database benchmark workload. Chinang has posted about > this before, but the thread didn't really go anywhere. > http://marc.info/?t=122903815000001&r=1&w=2 > >SLUB would have had a huge negative effect if we were using it -- on the >order of 7% iirc. SLQB is at least performance-neutral with SLAB. > >-- >Matthew Wilcox Intel Open Source Technology Centre >"Bill, look, we understand that you're interested in selling us this >operating system, but compare it to ours. We can't possibly take such >a retrograde step." -Chinang -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/