Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261644AbUCKSZv (ORCPT ); Thu, 11 Mar 2004 13:25:51 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261640AbUCKSZv (ORCPT ); Thu, 11 Mar 2004 13:25:51 -0500 Received: from mtagate1.de.ibm.com ([195.212.29.150]:22772 "EHLO mtagate1.de.ibm.com") by vger.kernel.org with ESMTP id S261629AbUCKSZr convert rfc822-to-8bit (ORCPT ); Thu, 11 Mar 2004 13:25:47 -0500 Subject: Re: blk_congestion_wait racy? To: Nick Piggin Cc: Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org X-Mailer: Lotus Notes Release 5.0.11 July 24, 2002 Message-ID: From: Martin Schwidefsky Date: Thu, 11 Mar 2004 19:24:48 +0100 X-MIMETrack: Serialize by Router on D12ML062/12/M/IBM(Release 6.0.2CF2|July 23, 2003) at 11/03/2004 19:25:04 MIME-Version: 1.0 Content-type: text/plain; charset=ISO-8859-1 Content-transfer-encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1331 Lines: 54 > Martin, have you tried adding this printk? Sorry for the delay. I had to get 2.6.4-mm1 working before doing the "ouch" test. The new pte_to_pgprot/pgoff_prot_to_pte stuff wasn't easy. I tested 2.6.4-mm1 with the blk_run_queues move and the ouch printk. The first interesting observation is that 2.6.4-mm1 behaves MUCH better then 2.6.4: 2.6.4-mm1 with 1 cpu # time ./mempig 600 Count (1Meg blocks) = 600 600 of 600 Done. real 0m2.587s user 0m0.100s sys 0m0.730s # 2.6.4-mm1 with 2 cpus # time ./mempig 600 Count (1Meg blocks) = 600 600 of 600 Done. real 0m10.313s user 0m0.160s sys 0m0.780s # 2.6.4 takes > 1min for the test with 2 cpus. The second observation is that I get only a few "ouch" messages. They all come from the blk_congestion_wait in try_to_free_pages, as expected. What I did not expect is that I only got 9 "ouches" for the run with 2 cpus. blue skies, Martin Linux/390 Design & Development, IBM Deutschland Entwicklung GmbH Sch?naicherstr. 220, D-71032 B?blingen, Telefon: 49 - (0)7031 - 16-2247 E-Mail: schwidefsky@de.ibm.com - 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/