From: Andrew Morton <akpm@linux-foundation.org>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wu Fengguang <fengguang.wu@intel.com>, Jan Kara <jack@suse.cz>,
Li Shaohua <shaohua.li@intel.com>, Christoph Hellwig <hch@lst.de>,
Dave Chinner <david@fromorbit.com>,
"Theodore Ts'o" <tytso@mit.edu>,
Chris Mason <chris.mason@oracle.com>, Mel Gorman <mel@csn.ul.ie>,
Rik van Riel <riel@redhat.com>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
linux-mm <linux-mm@kvack.org>,
linux-fsdevel@vger.kernel.org,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 06/13] writeback: bdi write bandwidth estimation
Date: Wed, 17 Nov 2010 15:38:27 -0800 [thread overview]
Message-ID: <20101117153827.e9f169d1.akpm@linux-foundation.org> (raw)
In-Reply-To: <1290036299.2109.1288.camel@laptop>
On Thu, 18 Nov 2010 00:24:59 +0100
Peter Zijlstra <a.p.zijlstra@chello.nl> wrote:
> On Wed, 2010-11-17 at 15:08 -0800, Andrew Morton wrote:
> > On Wed, 17 Nov 2010 12:27:26 +0800
> > Wu Fengguang <fengguang.wu@intel.com> wrote:
> >
> > > + w = min(elapsed / (HZ/100), 128UL);
> >
> > I did try setting HZ=10 many years ago, and the kernel blew up.
> >
> > I do recall hearing of people who set HZ very low, perhaps because
> > their huge machines were seeing performance prolems when the timer tick
> > went off. Probably there's no need to do that any more.
> >
> > But still, we shouldn't hard-wire the (HZ >= 100) assumption if we
> > don't absolutely need to, and I don't think it is absolutely needed
> > here.
>
> People who do cpu bring-up on very slow FPGAs also lower HZ as far as
> possible.
grep -r "[^a-zA-Z0-9_]HZ[ ]*/[ ]*100[^0-9]" .
:-(
WARNING: multiple messages have this Message-ID (diff)
From: Andrew Morton <akpm@linux-foundation.org>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wu Fengguang <fengguang.wu@intel.com>, Jan Kara <jack@suse.cz>,
Li Shaohua <shaohua.li@intel.com>, Christoph Hellwig <hch@lst.de>,
Dave Chinner <david@fromorbit.com>,
"Theodore Ts'o" <tytso@mit.edu>,
Chris Mason <chris.mason@oracle.com>, Mel Gorman <mel@csn.ul.ie>,
Rik van Riel <riel@redhat.com>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
linux-mm <linux-mm@kvack.org>,
linux-fsdevel@vger.kernel.org,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 06/13] writeback: bdi write bandwidth estimation
Date: Wed, 17 Nov 2010 15:38:27 -0800 [thread overview]
Message-ID: <20101117153827.e9f169d1.akpm@linux-foundation.org> (raw)
In-Reply-To: <1290036299.2109.1288.camel@laptop>
On Thu, 18 Nov 2010 00:24:59 +0100
Peter Zijlstra <a.p.zijlstra@chello.nl> wrote:
> On Wed, 2010-11-17 at 15:08 -0800, Andrew Morton wrote:
> > On Wed, 17 Nov 2010 12:27:26 +0800
> > Wu Fengguang <fengguang.wu@intel.com> wrote:
> >
> > > + w = min(elapsed / (HZ/100), 128UL);
> >
> > I did try setting HZ=10 many years ago, and the kernel blew up.
> >
> > I do recall hearing of people who set HZ very low, perhaps because
> > their huge machines were seeing performance prolems when the timer tick
> > went off. Probably there's no need to do that any more.
> >
> > But still, we shouldn't hard-wire the (HZ >= 100) assumption if we
> > don't absolutely need to, and I don't think it is absolutely needed
> > here.
>
> People who do cpu bring-up on very slow FPGAs also lower HZ as far as
> possible.
grep -r "[^a-zA-Z0-9_]HZ[ ]*/[ ]*100[^0-9]" .
:-(
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next prev parent reply other threads:[~2010-11-17 23:39 UTC|newest]
Thread overview: 162+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-17 4:27 [PATCH 00/13] IO-less dirty throttling v2 Wu Fengguang
2010-11-17 4:27 ` Wu Fengguang
2010-11-17 4:27 ` Wu Fengguang
2010-11-17 4:27 ` [PATCH 01/13] writeback: IO-less balance_dirty_pages() Wu Fengguang
2010-11-17 4:27 ` Wu Fengguang
2010-11-17 4:27 ` Wu Fengguang
2010-11-17 10:34 ` Minchan Kim
2010-11-17 10:34 ` Minchan Kim
2010-11-22 2:01 ` Wu Fengguang
2010-11-22 2:01 ` Wu Fengguang
2010-11-22 2:01 ` Wu Fengguang
2010-11-17 23:08 ` Andrew Morton
2010-11-17 23:08 ` Andrew Morton
2010-11-17 23:08 ` Andrew Morton
2010-11-18 13:04 ` Peter Zijlstra
2010-11-18 13:04 ` Peter Zijlstra
2010-11-18 13:26 ` Wu Fengguang
2010-11-18 13:26 ` Wu Fengguang
2010-11-18 13:40 ` Peter Zijlstra
2010-11-18 13:40 ` Peter Zijlstra
2010-11-18 14:02 ` Wu Fengguang
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
2010-12-01 23:03 ` Andrew Morton
2010-12-02 1:56 ` Wu Fengguang
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 2:42 ` Ted Ts'o
2010-12-06 9:52 ` Dmitry
2010-12-06 9:52 ` Dmitry
2010-12-06 9:52 ` Dmitry
2010-12-06 12:34 ` Ted Ts'o
2010-12-06 12:34 ` Ted Ts'o
2010-11-17 4:27 ` [PATCH 02/13] writeback: consolidate variable names in balance_dirty_pages() Wu Fengguang
2010-11-17 4:27 ` Wu Fengguang
2010-11-17 4:27 ` [PATCH 03/13] writeback: per-task rate limit on balance_dirty_pages() Wu Fengguang
2010-11-17 4:27 ` Wu Fengguang
2010-11-17 4:27 ` Wu Fengguang
2010-11-17 14:39 ` Wu Fengguang
2010-11-17 14:39 ` Wu Fengguang
2010-11-24 10:23 ` Peter Zijlstra
2010-11-24 10:23 ` Peter Zijlstra
2010-11-24 10:43 ` Wu Fengguang
2010-11-24 10:43 ` Wu Fengguang
2010-11-24 10:49 ` Peter Zijlstra
2010-11-24 10:49 ` Peter Zijlstra
2010-11-17 4:27 ` [PATCH 04/13] writeback: prevent duplicate balance_dirty_pages_ratelimited() calls Wu Fengguang
2010-11-17 4:27 ` Wu Fengguang
2010-11-17 4:27 ` Wu Fengguang
2010-11-17 4:27 ` [PATCH 05/13] writeback: account per-bdi accumulated written pages Wu Fengguang
2010-11-17 4:27 ` Wu Fengguang
2010-11-17 4:27 ` Wu Fengguang
2010-11-24 10:26 ` Peter Zijlstra
2010-11-24 10:26 ` Peter Zijlstra
2010-11-24 10:44 ` Wu Fengguang
2010-11-24 10:44 ` Wu Fengguang
2010-11-17 4:27 ` [PATCH 06/13] writeback: bdi write bandwidth estimation Wu Fengguang
2010-11-17 4:27 ` Wu Fengguang
2010-11-17 4:27 ` Wu Fengguang
2010-11-17 23:08 ` Andrew Morton
2010-11-17 23:08 ` Andrew Morton
2010-11-17 23:08 ` Andrew Morton
2010-11-17 23:24 ` Peter Zijlstra
2010-11-17 23:24 ` Peter Zijlstra
2010-11-17 23:38 ` Andrew Morton [this message]
2010-11-17 23:38 ` Andrew Morton
2010-11-17 23:43 ` Peter Zijlstra
2010-11-17 23:43 ` Peter Zijlstra
2010-11-18 6:51 ` Wu Fengguang
2010-11-18 6:51 ` Wu Fengguang
2010-11-24 10:58 ` Peter Zijlstra
2010-11-24 10:58 ` Peter Zijlstra
2010-11-24 14:06 ` Wu Fengguang
2010-11-24 14:06 ` Wu Fengguang
2010-11-24 11:05 ` Peter Zijlstra
2010-11-24 11:05 ` Peter Zijlstra
2010-11-24 12:10 ` Wu Fengguang
2010-11-24 12:10 ` Wu Fengguang
2010-11-24 12:50 ` Peter Zijlstra
2010-11-24 12:50 ` Peter Zijlstra
2010-11-24 13:14 ` Wu Fengguang
2010-11-24 13:14 ` Wu Fengguang
2010-11-24 13:20 ` Wu Fengguang
2010-11-24 13:20 ` Wu Fengguang
2010-11-24 13:42 ` Peter Zijlstra
2010-11-24 13:42 ` Peter Zijlstra
2010-11-24 13:46 ` Wu Fengguang
2010-11-24 13:46 ` Wu Fengguang
2010-11-24 14:12 ` Peter Zijlstra
2010-11-24 14:12 ` Peter Zijlstra
2010-11-24 14:21 ` Wu Fengguang
2010-11-24 14:21 ` Wu Fengguang
2010-11-24 14:31 ` Peter Zijlstra
2010-11-24 14:31 ` Peter Zijlstra
2010-11-24 14:38 ` Wu Fengguang
2010-11-24 14:38 ` Wu Fengguang
2010-11-24 14:34 ` Wu Fengguang
2010-11-24 14:34 ` Wu Fengguang
2010-11-17 4:27 ` [PATCH 07/13] writeback: show bdi write bandwidth in debugfs Wu Fengguang
2010-11-17 4:27 ` Wu Fengguang
2010-11-17 4:27 ` Wu Fengguang
2010-11-17 4:27 ` [PATCH 08/13] writeback: quit throttling when bdi dirty pages dropped low Wu Fengguang
2010-11-17 4:27 ` Wu Fengguang
2010-11-17 4:27 ` Wu Fengguang
2010-11-24 11:13 ` Peter Zijlstra
2010-11-24 11:13 ` Peter Zijlstra
2010-11-24 12:30 ` Wu Fengguang
2010-11-24 12:30 ` Wu Fengguang
2010-11-24 12:46 ` Peter Zijlstra
2010-11-24 12:46 ` Peter Zijlstra
2010-11-24 12:59 ` Wu Fengguang
2010-11-24 12:59 ` Wu Fengguang
2010-11-17 4:27 ` [PATCH 09/13] writeback: reduce per-bdi dirty threshold ramp up time Wu Fengguang
2010-11-17 4:27 ` Wu Fengguang
2010-11-17 4:27 ` Wu Fengguang
2010-11-24 11:15 ` Peter Zijlstra
2010-11-24 11:15 ` Peter Zijlstra
2010-11-24 12:39 ` Wu Fengguang
2010-11-24 12:39 ` Wu Fengguang
2010-11-24 12:56 ` Peter Zijlstra
2010-11-24 12:56 ` Peter Zijlstra
2010-11-17 4:27 ` [PATCH 10/13] writeback: make reasonable gap between the dirty/background thresholds Wu Fengguang
2010-11-17 4:27 ` Wu Fengguang
2010-11-17 4:27 ` Wu Fengguang
2010-11-24 11:18 ` Peter Zijlstra
2010-11-24 11:18 ` Peter Zijlstra
2010-11-24 12:48 ` Wu Fengguang
2010-11-24 12:48 ` Wu Fengguang
2010-11-17 4:27 ` [PATCH 11/13] writeback: scale down max throttle bandwidth on concurrent dirtiers Wu Fengguang
2010-11-17 4:27 ` Wu Fengguang
2010-11-17 4:27 ` Wu Fengguang
2010-11-17 4:27 ` [PATCH 12/13] writeback: add trace event for balance_dirty_pages() Wu Fengguang
2010-11-17 4:27 ` Wu Fengguang
2010-11-17 4:27 ` Wu Fengguang
2010-11-17 4:41 ` Wu Fengguang
2010-11-17 4:41 ` Wu Fengguang
2010-11-17 4:27 ` [PATCH 13/13] writeback: make nr_to_write a per-file limit Wu Fengguang
2010-11-17 4:27 ` Wu Fengguang
2010-11-17 4:27 ` Wu Fengguang
2010-11-17 23:03 ` [PATCH 00/13] IO-less dirty throttling v2 Andrew Morton
2010-11-17 23:03 ` Andrew Morton
2010-11-17 23:03 ` Andrew Morton
2010-11-18 2:06 ` Dave Chinner
2010-11-18 2:06 ` Dave Chinner
2010-11-18 2:09 ` Andrew Morton
2010-11-18 2:09 ` Andrew Morton
2010-11-18 3:21 ` Dave Chinner
2010-11-18 3:21 ` Dave Chinner
2010-11-18 3:34 ` Andrew Morton
2010-11-18 3:34 ` Andrew Morton
2010-11-18 7:27 ` Dave Chinner
2010-11-18 7:27 ` Dave Chinner
2010-11-18 7:33 ` Andrew Morton
2010-11-18 7:33 ` Andrew Morton
2010-11-19 3:11 ` Dave Chinner
2010-11-19 3:11 ` Dave Chinner
2010-11-24 11:12 ` Avi Kivity
2010-11-24 11:12 ` Avi Kivity
-- strict thread matches above, loose matches on Subject: below --
2010-11-17 3:58 [PATCH 06/13] writeback: bdi write bandwidth estimation Wu Fengguang
2010-11-17 3:58 ` Wu Fengguang
2010-11-17 3:58 ` Wu Fengguang
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