From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753828AbXCSMOX (ORCPT ); Mon, 19 Mar 2007 08:14:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753834AbXCSMOX (ORCPT ); Mon, 19 Mar 2007 08:14:23 -0400 Received: from py-out-1112.google.com ([64.233.166.183]:19993 "EHLO py-out-1112.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753828AbXCSMOV (ORCPT ); Mon, 19 Mar 2007 08:14:21 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:user-agent:mime-version:to:cc:subject:references:in-reply-to:content-type:content-transfer-encoding; b=JiNfeOecaaScIK2TKVTf+MEiUKKPsoepwqWL92EZtJsEJ2cPy54azJqcLCQS3Kzu4IOZK3pyH211enMP3EPCD5vEBzl6jI+z+RmjrqgMtWxxAcay1J/FqbGkTzAnRKic+pTSbsCq1aW0Xx1ZrtTKrmsunzrNH7h0B1vAxAAI5Ak= Message-ID: <45FE7E96.4050808@gmail.com> Date: Mon, 19 Mar 2007 21:14:14 +0900 From: Tejun Heo User-Agent: Icedove 1.5.0.10 (X11/20070307) MIME-Version: 1.0 To: Alan Cox CC: Tony Vroon , Jeff Garzik , linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2.6.22] Add LED trigger to libata core References: <20070318170605.3751D5B80F1@ganymede.vroon.org> <45FE14BD.5090701@gmail.com> <20070319124616.2fb7494b@lxorguk.ukuu.org.uk> In-Reply-To: <20070319124616.2fb7494b@lxorguk.ukuu.org.uk> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Alan Cox wrote: > On Mon, 19 Mar 2007 13:42:37 +0900 > Tejun Heo wrote: > >> Tony Vroon wrote: >>> This duplicates the IDE core LED trigger in the libata core. >>> I plan to use this by allowing PMU LED control on G5 towers. My test platform >>> is a PowerMac 7,3 (Dual G5 2.0GHz, June 2004) with a K2 (sata_svw) controller. >> I think this fits better in libata-core.c::ata_qc_issue(). Can you move >> it to there? > > Gak. I'd rather it stayed out of ata_qc_issue() which is a critical path > for performance. The original place is in the critical path too. It's just at the outer function which eventually calls ata_qc_issue() (the mapping is almost one to one). > Our command issu is already too heavy and not all > controllers have queueing to absorb that. How many controllers actually > need this hook and can we not have ata_qc_issue_with_led() helpers for > them ? Our issue path is somewhat expensive due to SCSI -> ATA translation but I don't think it really matters on any modern cpu. It can definitely hurt on embedded tho. :-( -- tejun