Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754168Ab3C0GNG (ORCPT ); Wed, 27 Mar 2013 02:13:06 -0400 Received: from LGEMRELSE6Q.lge.com ([156.147.1.121]:43387 "EHLO LGEMRELSE6Q.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751360Ab3C0GND (ORCPT ); Wed, 27 Mar 2013 02:13:03 -0400 X-AuditID: 9c930179-b7c78ae000000e4b-7e-51528decab8a Date: Wed, 27 Mar 2013 15:13:51 +0900 From: Joonsoo Kim To: Steven Rostedt Cc: Christoph Lameter , LKML , RT , Thomas Gleixner , Clark Williams Subject: Re: [RT LATENCY] 249 microsecond latency caused by slub's unfreeze_partials() code. Message-ID: <20130327061351.GB17125@lge.com> References: <1364010673.6345.156.camel@gandalf.local.home> <0000013da1f93be3-c3d42ae8-ff34-4c63-8094-77a83291ea19-000000@email.amazonses.com> <1364227073.6345.182.camel@gandalf.local.home> <1364228039.6345.183.camel@gandalf.local.home> <0000013da2ace21a-9e87fe8a-75c2-4b7c-b5e1-37ad196ce012-000000@email.amazonses.com> <1364234613.6345.184.camel@gandalf.local.home> <0000013da2ce20f8-0e3a64ef-67ed-4ab4-9f20-b77980c876c3-000000@email.amazonses.com> <1364236355.6345.185.camel@gandalf.local.home> <20130327025957.GA17125@lge.com> <1364355032.6345.200.camel@gandalf.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1364355032.6345.200.camel@gandalf.local.home> User-Agent: Mutt/1.5.21 (2010-09-15) X-Brightmail-Tracker: AAAAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1127 Lines: 33 On Tue, Mar 26, 2013 at 11:30:32PM -0400, Steven Rostedt wrote: > On Wed, 2013-03-27 at 11:59 +0900, Joonsoo Kim wrote: > > > How about using spin_try_lock() in unfreeze_partials() and > > using spin_lock_contented() in get_partial_node() to reduce latency? > > IMHO, this doesn't make code more deterministic, but can maintain > > a benefit of cpu partial page with tolerable latency. > > And what do you do when you fail the try lock? Try again, or just break > out? Just break out. > > We can run benchmarks, but I don't like playing games in -rt. It either > is deterministic, or it isn't. Okay. > > -- Steve > > > -- > 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/ -- 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/