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From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
To: Mel Gorman <mel@csn.ul.ie>
Cc: kosaki.motohiro@jp.fujitsu.com, Rob Mueller <robm@fastmail.fm>,
	linux-kernel@vger.kernel.org, Bron Gondwana <brong@fastmail.fm>,
	linux-mm <linux-mm@kvack.org>,
	Christoph Lameter <cl@linux-foundation.org>
Subject: Re: Default zone_reclaim_mode = 1 on NUMA kernel is bad forfile/email/web servers
Date: Mon, 27 Sep 2010 11:01:41 +0900 (JST)	[thread overview]
Message-ID: <20100927110049.6B31.A69D9226@jp.fujitsu.com> (raw)
In-Reply-To: <20100921090407.GA11439@csn.ul.ie>

Hi

> No doubt this is true. The only real difference is that there are more NUMA
> machines running mail/web/file servers now than there might have been in the
> past. The default made sense once upon a time. Personally I wouldn't mind
> the default changing but my preference would be that distribution packages
> installing on NUMA machines would prompt if the default should be changed if it
> is likely to be of benefit for that package (e.g. the mail, file and web ones).

At first impression, I thought this is cute idea. But, after while thinking, I've found some
weak point. The problem is, too many package need to disable zone_reclaim_mode.
zone_reclaim doesn't works fine if an application need large working set rather than
local node size. It mean major desktop applications (e.g. OpenOffice.org, Firefox, GIMP)
need to disable zone_reclaim. It mean even though basic package installation require 
zone_reclaim disabling. Then, this mechanism doesn't works practically. Even though
the user hope to use the machine for hpc, disable zone_reclaim will be turn on anyway.

Probably, opposite switch (default is zone_reclaim=0, and installation MPI library change
to zone_reclaim=1) might works. but I can guess why you don't propose this one.

Hmm....



WARNING: multiple messages have this Message-ID (diff)
From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
To: Mel Gorman <mel@csn.ul.ie>
Cc: kosaki.motohiro@jp.fujitsu.com, Rob Mueller <robm@fastmail.fm>,
	linux-kernel@vger.kernel.org, Bron Gondwana <brong@fastmail.fm>,
	linux-mm <linux-mm@kvack.org>,
	Christoph Lameter <cl@linux-foundation.org>
Subject: Re: Default zone_reclaim_mode = 1 on NUMA kernel is bad forfile/email/web servers
Date: Mon, 27 Sep 2010 11:01:41 +0900 (JST)	[thread overview]
Message-ID: <20100927110049.6B31.A69D9226@jp.fujitsu.com> (raw)
In-Reply-To: <20100921090407.GA11439@csn.ul.ie>

Hi

> No doubt this is true. The only real difference is that there are more NUMA
> machines running mail/web/file servers now than there might have been in the
> past. The default made sense once upon a time. Personally I wouldn't mind
> the default changing but my preference would be that distribution packages
> installing on NUMA machines would prompt if the default should be changed if it
> is likely to be of benefit for that package (e.g. the mail, file and web ones).

At first impression, I thought this is cute idea. But, after while thinking, I've found some
weak point. The problem is, too many package need to disable zone_reclaim_mode.
zone_reclaim doesn't works fine if an application need large working set rather than
local node size. It mean major desktop applications (e.g. OpenOffice.org, Firefox, GIMP)
need to disable zone_reclaim. It mean even though basic package installation require 
zone_reclaim disabling. Then, this mechanism doesn't works practically. Even though
the user hope to use the machine for hpc, disable zone_reclaim will be turn on anyway.

Probably, opposite switch (default is zone_reclaim=0, and installation MPI library change
to zone_reclaim=1) might works. but I can guess why you don't propose this one.

Hmm....


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  parent reply	other threads:[~2010-09-27  2:01 UTC|newest]

Thread overview: 61+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-09-13  3:39 Default zone_reclaim_mode = 1 on NUMA kernel is bad for file/email/web servers Robert Mueller
2010-09-16 10:01 ` KOSAKI Motohiro
2010-09-16 10:01   ` KOSAKI Motohiro
2010-09-16 17:06   ` Christoph Lameter
2010-09-16 17:06     ` Christoph Lameter
2010-09-17  0:50     ` Robert Mueller
2010-09-17  0:50       ` Robert Mueller
2010-09-17  6:01       ` Shaohua Li
2010-09-17  6:01         ` Shaohua Li
2010-09-17  7:32         ` Robert Mueller
2010-09-17  7:32           ` Robert Mueller
2010-09-17 13:56           ` Christoph Lameter
2010-09-17 13:56             ` Christoph Lameter
2010-09-17 14:09             ` Bron Gondwana
2010-09-17 14:09               ` Bron Gondwana
2010-09-17 14:22               ` Christoph Lameter
2010-09-17 14:22                 ` Christoph Lameter
2010-09-17 23:01                 ` Bron Gondwana
2010-09-17 23:01                   ` Bron Gondwana
2010-09-20  9:34   ` Mel Gorman
2010-09-20  9:34     ` Mel Gorman
2010-09-20 23:41     ` Default zone_reclaim_mode = 1 on NUMA kernel is bad forfile/email/web servers Rob Mueller
2010-09-20 23:41       ` Rob Mueller
2010-09-21  9:04       ` Mel Gorman
2010-09-21  9:04         ` Mel Gorman
2010-09-21 14:14         ` Christoph Lameter
2010-09-21 14:14           ` Christoph Lameter
2010-09-22  3:44           ` Rob Mueller
2010-09-22  3:44             ` Rob Mueller
2010-09-27  2:01         ` KOSAKI Motohiro [this message]
2010-09-27  2:01           ` KOSAKI Motohiro
2010-09-27 13:53           ` Christoph Lameter
2010-09-27 13:53             ` Christoph Lameter
2010-09-27 23:17             ` Robert Mueller
2010-09-27 23:17               ` Robert Mueller
2010-09-28 12:35               ` Christoph Lameter
2010-09-28 12:35                 ` Christoph Lameter
2010-09-28 12:42                 ` Bron Gondwana
2010-09-28 12:42                   ` Bron Gondwana
2010-09-28 12:49                   ` Christoph Lameter
2010-09-28 12:49                     ` Christoph Lameter
2010-09-30  7:05             ` Andi Kleen
2010-09-30  7:05               ` Andi Kleen
2010-10-04 12:45             ` KOSAKI Motohiro
2010-10-04 12:45               ` KOSAKI Motohiro
2010-10-04 13:07               ` Christoph Lameter
2010-10-04 13:07                 ` Christoph Lameter
2010-10-05  5:32                 ` KOSAKI Motohiro
2010-10-05  5:32                   ` KOSAKI Motohiro
2010-10-04 19:43               ` David Rientjes
2010-10-04 19:43                 ` David Rientjes
2010-09-21  1:05   ` Default zone_reclaim_mode = 1 on NUMA kernel is bad for file/email/web servers KAMEZAWA Hiroyuki
2010-09-21  1:05     ` KAMEZAWA Hiroyuki
2010-09-27  2:04     ` KOSAKI Motohiro
2010-09-27  2:04       ` KOSAKI Motohiro
2010-09-27  2:06       ` KAMEZAWA Hiroyuki
2010-09-27  2:06         ` KAMEZAWA Hiroyuki
2010-09-23 11:44   ` Balbir Singh
2010-09-23 11:44     ` Balbir Singh
2010-09-30  8:38   ` Bron Gondwana
2010-09-30  8:38     ` Bron Gondwana

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