From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759582Ab0KQETg (ORCPT ); Tue, 16 Nov 2010 23:19:36 -0500 Received: from mga02.intel.com ([134.134.136.20]:6205 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758083Ab0KQETf (ORCPT ); Tue, 16 Nov 2010 23:19:35 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.59,209,1288594800"; d="scan'208";a="574573425" Date: Wed, 17 Nov 2010 12:19:26 +0800 From: Wu Fengguang To: Andrew Morton Cc: "Theodore Ts'o" , Chris Mason , Dave Chinner , Jan Kara , Peter Zijlstra , Jens Axboe , Mel Gorman , Rik van Riel , KOSAKI Motohiro , Christoph Hellwig , linux-mm , "linux-fsdevel@vger.kernel.org" , LKML Subject: Re: [PATCH 01/13] writeback: IO-less balance_dirty_pages() Message-ID: <20101117041926.GA14209@localhost> References: <20101117035905.525232375@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20101117035905.525232375@intel.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 > BEHAVIOR CHANGE > =============== > > Users will notice that the applications will get throttled once the > crossing the global (background + dirty)/2=15% threshold. For a single > "cp", it could be soft throttled at 2*bdi->write_bandwidth around 15% s/2/8/ Sorry, the initial soft throttle bandwidth for "cp" is about 8 times of bdi bandwidth when reaching 15% dirty pages. > dirty pages, and be balanced at speed bdi->write_bandwidth around 17.5% > dirty pages. Before patch, the behavior is to just throttle it at 17.5% > dirty pages. > > Since the task will be soft throttled earlier than before, it may be > perceived by end users as performance "slow down" if his application > happens to dirty more than ~15% memory. From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wu Fengguang Subject: Re: [PATCH 01/13] writeback: IO-less balance_dirty_pages() Date: Wed, 17 Nov 2010 12:19:26 +0800 Message-ID: <20101117041926.GA14209@localhost> References: <20101117035905.525232375@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Theodore Ts'o , Chris Mason , Dave Chinner , Jan Kara , Peter Zijlstra , Jens Axboe , Mel Gorman , Rik van Riel , KOSAKI Motohiro , Christoph Hellwig , linux-mm , "linux-fsdevel@vger.kernel.org" , LKML To: Andrew Morton Return-path: Content-Disposition: inline In-Reply-To: <20101117035905.525232375@intel.com> Sender: owner-linux-mm@kvack.org List-Id: linux-fsdevel.vger.kernel.org > BEHAVIOR CHANGE > =============== > > Users will notice that the applications will get throttled once the > crossing the global (background + dirty)/2=15% threshold. For a single > "cp", it could be soft throttled at 2*bdi->write_bandwidth around 15% s/2/8/ Sorry, the initial soft throttle bandwidth for "cp" is about 8 times of bdi bandwidth when reaching 15% dirty pages. > dirty pages, and be balanced at speed bdi->write_bandwidth around 17.5% > dirty pages. Before patch, the behavior is to just throttle it at 17.5% > dirty pages. > > Since the task will be soft throttled earlier than before, it may be > perceived by end users as performance "slow down" if his application > happens to dirty more than ~15% memory. -- 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/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: email@kvack.org