From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alan Cox Subject: Re: sata_mv performance; impact of NCQ Date: Mon, 28 Apr 2008 18:53:38 +0100 Message-ID: <20080428185338.0368ff32@core> References: <20080426001657.GD17369@modernduck.com> <20080428171449.GI17369@modernduck.com> <48160C39.6000701@rtr.ca> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Received: from outpipe-village-512-1.bc.nu ([81.2.110.250]:48104 "EHLO lxorguk.ukuu.org.uk" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S934630AbYD1SBB (ORCPT ); Mon, 28 Apr 2008 14:01:01 -0400 In-Reply-To: <48160C39.6000701@rtr.ca> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Mark Lord Cc: Jody McIntyre , Grant Grundler , linux-ide@vger.kernel.org > Or at least that's how I understood Tejun's last explanation of it. > It is possible that the drive firmware in some brands may not follow > spec for FLUSH_CACHE_EXT, but I don't know of a specific instance of this. For an ATA device it should be ok - the standard purposefully specified flush cache functions in a way that was intended to stop drives lying for benchmarketing reasons and the like. So you should always get proper behaviour on any drive which implements it providing barriers are enabled on the fs.