From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from casper.infradead.org ([85.118.1.10]:43554 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756404Ab2JJOQR (ORCPT ); Wed, 10 Oct 2012 10:16:17 -0400 Message-ID: <50758306.7020807@kernel.dk> Date: Wed, 10 Oct 2012 08:15:34 -0600 From: Jens Axboe MIME-Version: 1.0 Subject: Re: FIO 2.0.9 for Windows Server 2008 RC1 SP2 reports extreme latencies References: <50605FEF.5020103@cran.org.uk> <50632E0D.4090003@cran.org.uk> <506693F8.3010903@kernel.dk> <5066FBC0.5040508@cran.org.uk> <507548FE.9010106@cran.org.uk> <507550DB.2000301@cran.org.uk> In-Reply-To: <507550DB.2000301@cran.org.uk> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: fio-owner@vger.kernel.org List-Id: fio@vger.kernel.org To: Bruce Cran Cc: "Jeffrey McVay (jmcvay)" , "fio@vger.kernel.org" On 2012-10-10 04:41, Bruce Cran wrote: > On 10/10/2012 11:07, Bruce Cran wrote: >> The problem is that windowsaio iterates over the list of outstanding >> IOs (busylist), but that list has the most recent first. > > The attached patch appears to fix the problem: > > Add outstanding IOs to the tail of io_u_busylist, not the head. So where is this bug exactly? Is Windows reaping events from the head of this list, and thus starving indefinitely potentially? Patch makes sense in any case, but it should not make a functional difference. I'll apply it. -- Jens Axboe