From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752103Ab0HTCvS (ORCPT ); Thu, 19 Aug 2010 22:51:18 -0400 Received: from mga09.intel.com ([134.134.136.24]:58125 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751059Ab0HTCvQ (ORCPT ); Thu, 19 Aug 2010 22:51:16 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.56,236,1280732400"; d="scan'208";a="547026157" Date: Fri, 20 Aug 2010 10:51:11 +0800 From: Wu Fengguang To: Michael Rubin Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, jack@suse.cz, riel@redhat.com, akpm@linux-foundation.org, david@fromorbit.com, npiggin@suse.de, hch@lst.de, axboe@kernel.dk Subject: Re: [PATCH 2/3] writeback: Adding pages_dirtied and pages_entered_writeback Message-ID: <20100820025111.GB5502@localhost> References: <1282251447-16937-1-git-send-email-mrubin@google.com> <1282251447-16937-3-git-send-email-mrubin@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1282251447-16937-3-git-send-email-mrubin@google.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Aug 19, 2010 at 01:57:26PM -0700, Michael Rubin wrote: > To help developers and applications gain visibility into writeback > behaviour adding four read only sysctl files into /proc/sys/vm. > These files allow user apps to understand writeback behaviour over time > and learn how it is impacting their performance. > > # cat /proc/sys/vm/pages_dirtied > 3747 > # cat /proc/sys/vm/pages_entered_writeback > 3618 As Rik said, /proc/sys is not a suitable place. Frankly speaking I've worked on writeback for years and never felt the need to add these counters. What I often do is: $ vmmon -d 1 nr_writeback nr_dirty nr_unstable nr_writeback nr_dirty nr_unstable 68738 0 39568 66051 0 42255 63406 0 44900 60643 0 47663 57954 0 50352 55264 0 53042 52592 0 55715 49922 0 58385 That is what I get when copying /dev/zero to NFS. You can find vmmon.c in Andrew Morton's ext3-tools package. Also attached for your convenience. I'm very interested in Google's use case for this patch, and why the simple /proc/vmstat based vmmon tool is not enough. Thanks, Fengguang From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wu Fengguang Subject: Re: [PATCH 2/3] writeback: Adding pages_dirtied and pages_entered_writeback Date: Fri, 20 Aug 2010 10:51:11 +0800 Message-ID: <20100820025111.GB5502@localhost> References: <1282251447-16937-1-git-send-email-mrubin@google.com> <1282251447-16937-3-git-send-email-mrubin@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, jack@suse.cz, riel@redhat.com, akpm@linux-foundation.org, david@fromorbit.com, npiggin@suse.de, hch@lst.de, axboe@kernel.dk To: Michael Rubin Return-path: Content-Disposition: inline In-Reply-To: <1282251447-16937-3-git-send-email-mrubin@google.com> Sender: owner-linux-mm@kvack.org List-Id: linux-fsdevel.vger.kernel.org On Thu, Aug 19, 2010 at 01:57:26PM -0700, Michael Rubin wrote: > To help developers and applications gain visibility into writeback > behaviour adding four read only sysctl files into /proc/sys/vm. > These files allow user apps to understand writeback behaviour over time > and learn how it is impacting their performance. > > # cat /proc/sys/vm/pages_dirtied > 3747 > # cat /proc/sys/vm/pages_entered_writeback > 3618 As Rik said, /proc/sys is not a suitable place. Frankly speaking I've worked on writeback for years and never felt the need to add these counters. What I often do is: $ vmmon -d 1 nr_writeback nr_dirty nr_unstable nr_writeback nr_dirty nr_unstable 68738 0 39568 66051 0 42255 63406 0 44900 60643 0 47663 57954 0 50352 55264 0 53042 52592 0 55715 49922 0 58385 That is what I get when copying /dev/zero to NFS. You can find vmmon.c in Andrew Morton's ext3-tools package. Also attached for your convenience. I'm very interested in Google's use case for this patch, and why the simple /proc/vmstat based vmmon tool is not enough. Thanks, Fengguang -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org