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From: Wu Fengguang <fengguang.wu@intel.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: "Theodore Ts'o" <tytso@mit.edu>,
	Chris Mason <chris.mason@oracle.com>,
	Dave Chinner <david@fromorbit.com>, Jan Kara <jack@suse.cz>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Jens Axboe <axboe@kernel.dk>, Mel Gorman <mel@csn.ul.ie>,
	Rik van Riel <riel@redhat.com>,
	KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
	Christoph Hellwig <hch@lst.de>, linux-mm <linux-mm@kvack.org>,
	"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 01/13] writeback: IO-less balance_dirty_pages()
Date: Wed, 17 Nov 2010 12:19:26 +0800	[thread overview]
Message-ID: <20101117041926.GA14209@localhost> (raw)
In-Reply-To: <20101117035905.525232375@intel.com>

> 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.

  reply	other threads:[~2010-11-17  4:19 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-11-17  3:58 [PATCH 01/13] writeback: IO-less balance_dirty_pages() Wu Fengguang
2010-11-17  4:19 ` Wu Fengguang [this message]
2010-11-17  8:33   ` Wu Fengguang
2010-11-17  4:30 ` Wu Fengguang
2010-11-17  4:27 [PATCH 00/13] IO-less dirty throttling v2 Wu Fengguang
2010-11-17  4:27 ` [PATCH 01/13] writeback: IO-less balance_dirty_pages() Wu Fengguang
2010-11-17 10:34   ` Minchan Kim
2010-11-22  2:01     ` Wu Fengguang
2010-11-17 23:08   ` Andrew Morton
2010-11-18 13:04   ` Peter Zijlstra
2010-11-18 13:26     ` Wu Fengguang
2010-11-18 13:40       ` Peter Zijlstra
2010-11-18 14:02         ` Wu Fengguang
     [not found]     ` <20101129151719.GA30590@localhost>
     [not found]       ` <1291064013.32004.393.camel@laptop>
     [not found]         ` <20101130043735.GA22947@localhost>
     [not found]           ` <1291156522.32004.1359.camel@laptop>
     [not found]             ` <1291156765.32004.1365.camel@laptop>
     [not found]               ` <20101201133818.GA13377@localhost>
2010-12-01 23:03                 ` Andrew Morton
2010-12-02  1:56                   ` Wu Fengguang
2010-12-05 16:14                 ` Wu Fengguang
2010-12-06  2:42                   ` Ted Ts'o
2010-12-06  9:52                     ` Dmitry
2010-12-06 12:34                       ` Ted Ts'o

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