From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750702AbVHXHTi (ORCPT ); Wed, 24 Aug 2005 03:19:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750707AbVHXHTi (ORCPT ); Wed, 24 Aug 2005 03:19:38 -0400 Received: from omx3-ext.sgi.com ([192.48.171.20]:45470 "EHLO omx3.sgi.com") by vger.kernel.org with ESMTP id S1750702AbVHXHTh (ORCPT ); Wed, 24 Aug 2005 03:19:37 -0400 Date: Wed, 24 Aug 2005 17:19:31 +1000 From: Nathan Scott To: Jens Axboe Cc: Linux Kernel Subject: Re: [PATCH] blk queue io tracing support Message-ID: <20050824171931.H4209301@wobbly.melbourne.sgi.com> References: <20050823123235.GG16461@suse.de> <20050824010346.GA1021@frodo> <20050824070809.GA27956@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <20050824070809.GA27956@suse.de>; from axboe@suse.de on Wed, Aug 24, 2005 at 09:08:10AM +0200 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 24, 2005 at 09:08:10AM +0200, Jens Axboe wrote: > ... > This isn't msec precision, it's usec. sched_clock() is in ns! I already > decided that msec is too coarse, but usec _should_ be enough. Right you are (I was thinking m-for-micro, not m-for-milli in my head ;) - but still, there doesn't seem to be any reason for that divide-by-1000 and reducing the precision in the kernel rather than in userspace, does there? Doing it the other way means you wont ever have to worry about whether it is/isn't sufficient precision for all possible block devices, and the precision the tool displays will just be a userspace decision. cheers. -- Nathan