From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753128AbYAPT6S (ORCPT ); Wed, 16 Jan 2008 14:58:18 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750884AbYAPT6K (ORCPT ); Wed, 16 Jan 2008 14:58:10 -0500 Received: from e2.ny.us.ibm.com ([32.97.182.142]:59642 "EHLO e2.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750824AbYAPT6I (ORCPT ); Wed, 16 Jan 2008 14:58:08 -0500 Subject: Re: [rfc] lockless get_user_pages for dio (and more) From: Dave Kleikamp To: Nick Piggin Cc: "Siddha, Suresh B" , Ken Chen , Badari Pulavarty , linux-mm , tony.luck@intel.com, Adam Litke , linux-kernel In-Reply-To: <200712121640.17077.nickpiggin@yahoo.com.au> References: <20071008225234.GC27824@linux-os.sc.intel.com> <200712121557.20807.nickpiggin@yahoo.com.au> <1197436306.6367.12.camel@norville.austin.ibm.com> <200712121640.17077.nickpiggin@yahoo.com.au> Content-Type: text/plain Date: Wed, 16 Jan 2008 13:58:02 -0600 Message-Id: <1200513482.6935.15.camel@norville.austin.ibm.com> Mime-Version: 1.0 X-Mailer: Evolution 2.12.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2007-12-12 at 16:40 +1100, Nick Piggin wrote: > On Wednesday 12 December 2007 16:11, Dave Kleikamp wrote: > > On Wed, 2007-12-12 at 15:57 +1100, Nick Piggin wrote: > > > Anyway, I am hoping that someone will one day and test if this and > > > find it helps their workload, but on the other hand, if it doesn't > > > help anyone then we don't have to worry about adding it to the > > > kernel ;) I don't have any real setups that hammers DIO with threads. > > > I'm guessing DB2 and/or Oracle does? > > > > I'll try to get someone to run a DB2 benchmark and see what it looks > > like. > > That would be great if you could. We weren't able to get in any runs before the holidays, but we finally have some good news from our performance team: "To test the effects of the patch, an OLTP workload was run on an IBM x3850 M2 server with 2 processors (quad-core Intel Xeon processors at 2.93 GHz) using IBM DB2 v9.5 running Linux 2.6.24rc7 kernel. Comparing runs with and without the patch resulted in an overall performance benefit of ~9.8%. Correspondingly, oprofiles showed that samples from __up_read and __down_read routines that is seen during thread contention for system resources was reduced from 2.8% down to .05%. Monitoring the /proc/vmstat output from the patched run showed that the counter for fast_gup contained a very high number while the fast_gup_slow value was zero." Great work, Nick! Thanks, Shaggy -- David Kleikamp IBM Linux Technology Center