Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1765523AbZAQQvU (ORCPT ); Sat, 17 Jan 2009 11:51:20 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757440AbZAQQvE (ORCPT ); Sat, 17 Jan 2009 11:51:04 -0500 Received: from mail-bw0-f21.google.com ([209.85.218.21]:47114 "EHLO mail-bw0-f21.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754297AbZAQQvC (ORCPT ); Sat, 17 Jan 2009 11:51:02 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version :content-type:content-transfer-encoding:content-disposition :references; b=osqFrVbttkmN/swynvfdcqoqRkvuXobSTK25K2HLD/FqwhepIzT0Njrqx/Go1QRNpE pEjwl0LxdXmLfSeWd+YgUQwzEB2qVURokaHgy1NWXP2pr+6/VGXrvIbKyHinRGAPGyr+ SAP/DvbzFNGWQlKa889bUuBpd+o/zGE1AL8MM= Message-ID: Date: Sat, 17 Jan 2009 17:50:59 +0100 From: "Leon Woestenberg" To: "Mathieu Desnoyers" Subject: Re: [RFC PATCH] block: Fix bio merge induced high I/O latency Cc: "Jens Axboe" , "Andrea Arcangeli" , akpm@linux-foundation.org, "Ingo Molnar" , "Linus Torvalds" , linux-kernel@vger.kernel.org, ltt-dev@lists.casi.polymtl.ca, "Thomas Gleixner" In-Reply-To: <20090117162657.GA31965@Krystal> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <20090117004439.GA11492@Krystal> <20090117162657.GA31965@Krystal> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1022 Lines: 30 Hello Mathieu et al, On Sat, Jan 17, 2009 at 5:26 PM, Mathieu Desnoyers wrote: > A long standing I/O regression (since 2.6.18, still there today) has hit > Slashdot recently : > http://bugzilla.kernel.org/show_bug.cgi?id=12309 Are you sure you are solving the *actual* problem? The bugzilla entry shows a bisect attempt that leads to a patch involving negative clock jumps. http://bugzilla.kernel.org/show_bug.cgi?id=12309#c29 with a corrected link to the bisect patch: http://bugzilla.kernel.org/show_bug.cgi?id=12309#c30 Wouldn't a negative clock jump be very influential to the (time-driven) I/O schedulers and be a more probable cause? Regards, -- Leon p.s. Added Thomas to the CC list as his name is on the patch Signed-off-by list. -- 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/