Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756388Ab3C0Dah (ORCPT ); Tue, 26 Mar 2013 23:30:37 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:5525 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751212Ab3C0Daf (ORCPT ); Tue, 26 Mar 2013 23:30:35 -0400 X-Authority-Analysis: v=2.0 cv=H5hZMpki c=1 sm=0 a=rXTBtCOcEpjy1lPqhTCpEQ==:17 a=mNMOxpOpBa8A:10 a=ZzSxI7jMevMA:10 a=5SG0PmZfjMsA:10 a=IkcTkHD0fZMA:10 a=meVymXHHAAAA:8 a=mVTtbqeYs4EA:10 a=oHGkYV5a6l2hHoJyKb8A:9 a=QEXdDO2ut3YA:10 a=rXTBtCOcEpjy1lPqhTCpEQ==:117 X-Cloudmark-Score: 0 X-Authenticated-User: X-Originating-IP: 74.67.115.198 Message-ID: <1364355032.6345.200.camel@gandalf.local.home> Subject: Re: [RT LATENCY] 249 microsecond latency caused by slub's unfreeze_partials() code. From: Steven Rostedt To: Joonsoo Kim Cc: Christoph Lameter , LKML , RT , Thomas Gleixner , Clark Williams Date: Tue, 26 Mar 2013 23:30:32 -0400 In-Reply-To: <20130327025957.GA17125@lge.com> References: <1363906545.6345.81.camel@gandalf.local.home> <0000013d92c37ff3-5fb85400-bec1-4eda-8ba1-332566884c59-000000@email.amazonses.com> <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> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.4.4-2 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 750 Lines: 21 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? We can run benchmarks, but I don't like playing games in -rt. It either is deterministic, or it isn't. -- 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/