From: Hans Reiser <reiser@namesys.com>
To: Alexander Viro <viro@math.psu.edu>
Cc: Daniel Phillips <phillips@bonn-fries.net>,
Linus Torvalds <torvalds@transmeta.com>,
Josh MacDonald <jmacd@CS.Berkeley.EDU>,
linux-kernel@vger.kernel.org, reiserfs-list@namesys.com,
reiserfs-dev@namesys.com
Subject: Re: [reiserfs-dev] Re: Note describing poor dcache utilization under high memory pressure
Date: Tue, 29 Jan 2002 13:46:43 +0300 [thread overview]
Message-ID: <3C567D93.7030602@namesys.com> (raw)
In-Reply-To: <Pine.GSO.4.21.0201281927320.6592-100000@weyl.math.psu.edu>
Alexander Viro wrote:
>
>On Tue, 29 Jan 2002, Hans Reiser wrote:
>
>>This fails to recover an object (e.g. dcache entry) which is used once,
>>and then spends a year in cache on the same page as an object which is
>>hot all the time. This means that the hot set of objects becomes
>>diffused over an order of magnitude more pages than if garbage
>>collection squeezes them all together. That makes for very poor caching.
>>
>
>Any GC that is going to move active dentries around is out of question.
>It would need a locking of such strength that you would be the first
>to cry bloody murder - about 5 seconds after you look at the scalability
>benchmarks.
>
>
I don't mean to suggest that the dentry cache locking is an easy problem
to solve, but the problem discussed is a real one, and it is sufficient
to illustrate that the unified cache is fundamentally flawed as an
algorithm compared to using subcache plugins.
Hans
next prev parent reply other threads:[~2002-01-29 10:47 UTC|newest]
Thread overview: 85+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-01-28 17:13 Note describing poor dcache utilization under high memory pressure Josh MacDonald
2002-01-28 17:39 ` Linus Torvalds
2002-01-28 18:01 ` Rik van Riel
2002-01-28 18:21 ` Linus Torvalds
2002-01-28 18:37 ` Rik van Riel
2002-01-28 19:28 ` William Lee Irwin III
2002-01-28 20:01 ` Daniel Phillips
2002-01-28 21:33 ` Rick Stevens
2002-01-28 21:43 ` Rik van Riel
2002-01-28 22:00 ` Rick Stevens
2002-01-28 22:43 ` Daniel Phillips
2002-01-28 23:06 ` Rick Stevens
2002-01-28 23:51 ` [OT] " jepler
2002-01-29 2:30 ` IPmonger
2002-01-29 12:02 ` Karl & Betty Schendel
2002-01-28 22:26 ` Daniel Phillips
2002-01-28 22:34 ` Brian Gerst
2002-01-28 23:08 ` Daniel Phillips
2002-01-28 22:39 ` Daniel Phillips
2002-01-28 23:12 ` Rick Stevens
2002-01-28 23:27 ` Daniel Phillips
2002-01-28 22:01 ` Momchil Velikov
2002-01-28 22:19 ` Daniel Phillips
2002-01-29 1:29 ` Oliver Xymoron
2002-01-29 1:37 ` [reiserfs-list] " Valdis.Kletnieks
2002-01-29 1:45 ` Daniel Phillips
2002-01-29 8:39 ` Momchil Velikov
2002-01-29 8:55 ` Daniel Phillips
2002-01-29 9:20 ` William Lee Irwin III
2002-01-29 9:55 ` Daniel Phillips
2002-01-29 10:18 ` Momchil Velikov
2002-01-29 19:55 ` William Lee Irwin III
2002-01-29 20:08 ` Linus Torvalds
2002-01-29 20:39 ` William Lee Irwin III
2002-01-29 20:49 ` Linus Torvalds
2002-01-29 21:01 ` William Lee Irwin III
2002-01-29 9:20 ` Momchil Velikov
2002-01-29 10:27 ` Daniel Phillips
2002-01-29 11:54 ` Helge Hafting
2002-01-29 12:33 ` Daniel Phillips
2002-01-30 9:07 ` Horst von Brand
2002-01-30 10:55 ` Daniel Phillips
2002-01-30 14:46 ` Rik van Riel
2002-01-30 14:59 ` Daniel Phillips
2002-01-30 15:54 ` Rik van Riel
2002-01-30 16:34 ` Daniel Phillips
2002-01-29 10:59 ` Rik van Riel
2002-01-29 11:28 ` Daniel Phillips
2002-01-29 11:38 ` Rik van Riel
2002-01-29 12:01 ` Daniel Phillips
2002-01-29 16:57 ` Oliver Xymoron
2002-01-29 17:25 ` Rik van Riel
2002-01-29 20:48 ` Daniel Phillips
2002-01-29 21:00 ` Oliver Xymoron
2002-01-29 21:08 ` Linus Torvalds
2002-01-29 21:13 ` Oliver Xymoron
2002-01-29 21:50 ` Linus Torvalds
2002-01-29 22:02 ` Oliver Xymoron
2002-01-29 22:10 ` Linus Torvalds
2002-01-29 22:53 ` Daniel Phillips
2002-01-29 22:53 ` Daniel Phillips
2002-01-29 23:02 ` Oliver Xymoron
2002-01-29 23:21 ` Daniel Phillips
2002-01-28 19:25 ` [reiserfs-dev] " Hans Reiser
2002-01-28 23:52 ` Daniel Phillips
2002-01-29 0:16 ` Hans Reiser
2002-01-29 0:30 ` Alexander Viro
2002-01-29 10:46 ` Hans Reiser [this message]
2002-01-29 14:50 ` Chris Mason
2002-01-29 21:10 ` Hans Reiser
2002-01-30 7:11 ` Oliver Xymoron
2002-01-30 9:57 ` Hans Reiser
2002-01-29 17:28 ` Josh MacDonald
2002-01-29 18:44 ` [reiserfs-list] " Andreas Dilger
2002-01-29 19:55 ` Andrew Morton
2002-01-30 7:17 ` Oliver Xymoron
2002-01-30 7:32 ` [reiserfs-list] Re: [reiserfs-dev] Re: Note describing poordcache " Andrew Morton
2002-01-30 7:52 ` Oliver Xymoron
2002-01-30 10:03 ` Hans Reiser
2002-01-30 10:07 ` [reiserfs-dev] Re: Note describing poor dcache " Horst von Brand
2002-01-29 18:29 ` Horst von Brand
2002-01-29 0:51 ` Daniel Phillips
2002-01-29 1:32 ` Daniel Phillips
2002-01-28 22:46 ` Alex Bligh - linux-kernel
2002-01-29 17:27 ` Josh MacDonald
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=3C567D93.7030602@namesys.com \
--to=reiser@namesys.com \
--cc=jmacd@CS.Berkeley.EDU \
--cc=linux-kernel@vger.kernel.org \
--cc=phillips@bonn-fries.net \
--cc=reiserfs-dev@namesys.com \
--cc=reiserfs-list@namesys.com \
--cc=torvalds@transmeta.com \
--cc=viro@math.psu.edu \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox