From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.fusionio.com ([66.114.96.31]:49838 "EHLO mx2.fusionio.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932137Ab2BBTQO (ORCPT ); Thu, 2 Feb 2012 14:16:14 -0500 Message-ID: <4F2AE0FB.3020201@fusionio.com> Date: Thu, 2 Feb 2012 20:16:11 +0100 From: Jens Axboe MIME-Version: 1.0 Subject: Re: A commented out optimization... References: <4F28F62E.4060708@fusionio.com> <4F2A4345.5050007@fusionio.com> In-Reply-To: Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Sender: fio-owner@vger.kernel.org List-Id: fio@vger.kernel.org To: Steven Lang Cc: "fio@vger.kernel.org" On 2012-02-02 20:13, Steven Lang wrote: > The only thing I can think is maybe there was some sort of other issue > where perhaps a DMA IO was happening before the memory write, > unrelated to any of the code there, but the write barrier just > happened to fix it. But even that seems like it would be a bit of a > stretch to imagine it actually being a problem. I was thinking that could've been the issue as well, but in that case it would be a kernel (or driver) bug in that it didn't flush. -- Jens Axboe