Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161942AbWKPG7V (ORCPT ); Thu, 16 Nov 2006 01:59:21 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1161947AbWKPG7V (ORCPT ); Thu, 16 Nov 2006 01:59:21 -0500 Received: from brick.kernel.dk ([62.242.22.158]:45375 "EHLO kernel.dk") by vger.kernel.org with ESMTP id S1161942AbWKPG7U (ORCPT ); Thu, 16 Nov 2006 01:59:20 -0500 Date: Thu, 16 Nov 2006 07:58:47 +0100 From: Jens Axboe To: Edward Falk Cc: linux-kernel@vger.kernel.org, Andrew Morton Subject: Re: [PATCH] Introduce block I/O performance histograms Message-ID: <20061116065846.GE32394@kernel.dk> References: <455BD7E8.9020303@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <455BD7E8.9020303@google.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1249 Lines: 30 On Wed, Nov 15 2006, Edward Falk wrote: > This patch introduces performance histogram record keeping for block > I/O, used for performance tuning. It is turned off by default. > > When turned on, you simply do something like: > > # cat /sys/block/sda/read_request_histo > rows = bytes columns = ms > 10 20 50 100 200 500 1000 2000 > 2048 5 0 0 0 0 0 0 0 > 4096 0 0 0 0 0 0 0 0 > 8192 17231 135 41 10 0 0 0 0 > 16384 4400 24 6 2 0 0 0 0 > 32768 2897 34 4 4 0 0 0 0 > 65536 7089 87 5 1 2 0 0 0 I don't see the point at all for including this piece of code in the kernel. You can do the same from user space. Your help entry said it even grows the kernel size about 21k, that's pretty nasty. So NAK. -- Jens Axboe - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/