From: Linus Torvalds <torvalds@osdl.org>
To: Marcelo Tosatti <marcelo.tosatti@cyclades.com>
Cc: Andrew Morton <akpm@osdl.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
bob.picco@hp.com, iwamoto@valinux.co.jp, christoph@lameter.com,
wfg@mail.ustc.edu.cn, npiggin@suse.de, riel@redhat.com
Subject: Re: [PATCH 00/34] mm: Page Replacement Policy Framework
Date: Thu, 23 Mar 2006 12:49:00 -0800 (PST) [thread overview]
Message-ID: <Pine.LNX.4.64.0603231243160.26286@g5.osdl.org> (raw)
In-Reply-To: <20060323223057.GA12895@dmt.cnet>
On Thu, 23 Mar 2006, Marcelo Tosatti wrote:
>
> Nope, LRU only beat CLOCK-Pro/CART on the "UMass trace" (which is trace
> replay, which can be very sensitive and not necessarily meaningful).
> Needs more study though (talk is cheap).
Umm.. That _trace_ was the only thing that seemed to have any real-life
dataset, afaik. The others were totally synthetic.
> Anyway, smarter algorithms such as this two have been proven to be more
> efficient than LRU under a large range of real life loads. LRU's lack of
> frequency information is really terrible.
>
> LRU's worst case scenarios were well known before I was born.
The kernel doesn't actually use LRU, so the fact that LRU isn't good seems
a non-argument.
> - "Every time I wake up in the morning updatedb has thrown my applications
> out of memory".
>
> - "Linux is awful every time I untar something larger than memory to disk".
People seem to think that the fact that there are bad behaviours means
that there are somehow "magic" algorithms that don't have bad behaviours.
I'd really suggest somebody show better real-life numbers with a new
algorithm _before_ we do anything like this.
Linus
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next prev parent reply other threads:[~2006-03-23 20:49 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-03-22 22:31 Peter Zijlstra
2006-03-22 22:31 ` [PATCH 01/34] mm: kill-page-activate.patch Peter Zijlstra
2006-03-22 22:32 ` [PATCH 02/34] mm: page-replace-kconfig-makefile.patch Peter Zijlstra
2006-03-22 23:03 ` Jeff Garzik
2006-03-22 22:32 ` [PATCH 03/34] mm: page-replace-insert.patch Peter Zijlstra
2006-03-22 22:32 ` [PATCH 04/34] mm: page-replace-use_once.patch Peter Zijlstra
2006-03-22 22:32 ` [PATCH 05/34] mm: page-replace-generic-pagevec.patch Peter Zijlstra
2006-03-22 22:32 ` [PATCH 06/34] mm: page-replace-activate.patch Peter Zijlstra
2006-03-22 22:32 ` [PATCH 07/34] mm: page-replace-move-macros.patch Peter Zijlstra
2006-03-22 22:33 ` [PATCH 08/34] mm: page-replace-move-scan_control.patch Peter Zijlstra
2006-03-22 22:33 ` [PATCH 09/34] mm: page-replace-move-isolate_lru_pages.patch Peter Zijlstra
2006-03-22 22:33 ` [PATCH 10/34] mm: page-replace-reinsert.patch Peter Zijlstra
2006-03-22 22:33 ` [PATCH 11/34] mm: page-replace-should_reclaim_mapped.patch Peter Zijlstra
2006-03-22 22:33 ` [PATCH 12/34] mm: page-replace-shrink.patch Peter Zijlstra
2006-03-22 22:33 ` [PATCH 13/34] mm: page-replace-mark-accessed.patch Peter Zijlstra
2006-03-22 22:34 ` [PATCH 14/34] mm: page-replace-remove-mm_inline.patch Peter Zijlstra
2006-03-22 22:34 ` [PATCH 15/34] mm: page-replace-rotate.patch Peter Zijlstra
2006-03-22 22:34 ` [PATCH 16/34] mm: page-replace-init.patch Peter Zijlstra
2006-03-22 22:34 ` [PATCH 17/34] mm: page-replace-info.patch Peter Zijlstra
2006-03-22 22:34 ` [PATCH 18/34] mm: page-replace-counts.patch Peter Zijlstra
2006-03-22 22:34 ` [PATCH 19/34] mm: page-replace-data.patch Peter Zijlstra
2006-03-22 22:35 ` [PATCH 20/34] mm: page-replace-pg_flags.patch Peter Zijlstra
2006-03-22 22:35 ` [PATCH 21/34] mm: page-replace-nonresident.patch Peter Zijlstra
2006-03-22 22:35 ` [PATCH 22/34] mm: page-replace-shrink-new.patch Peter Zijlstra
2006-03-22 22:35 ` [PATCH 23/34] mm: page-replace-documentation.patch Peter Zijlstra
2006-03-22 22:35 ` [PATCH 24/34] mm: sum_cpu_var.patch Peter Zijlstra
2006-03-22 22:35 ` [PATCH 25/34] mm: kswapd-writeout-wait.patch Peter Zijlstra
2006-03-22 22:36 ` [PATCH 26/34] mm: clockpro-nonresident.patch Peter Zijlstra
2006-03-22 22:36 ` [PATCH 27/34] mm: clockpro-ignore_token.patch Peter Zijlstra
2006-03-22 22:36 ` [PATCH 28/34] mm: clockpro-PG_reclaim2.patch Peter Zijlstra
2006-03-22 22:36 ` [PATCH 29/34] mm: clockpro-clockpro.patch Peter Zijlstra
2006-03-22 22:36 ` [PATCH 30/34] mm: cart-nonresident.patch Peter Zijlstra
2006-03-22 22:36 ` [PATCH 31/34] mm: cart-PG_reclaim3.patch Peter Zijlstra
2006-03-22 22:37 ` [PATCH 32/34] mm: cart-cart.patch Peter Zijlstra
2006-03-22 22:37 ` [PATCH 33/34] mm: cart-r.patch Peter Zijlstra
2006-03-22 22:37 ` [PATCH 34/34] mm: random.patch Peter Zijlstra
2006-03-22 22:51 ` [PATCH 00/34] mm: Page Replacement Policy Framework Andrew Morton
2006-03-23 2:21 ` Nick Piggin
2006-03-23 21:13 ` Marcelo Tosatti
2006-03-23 4:01 ` Rik van Riel
2006-03-23 20:53 ` Marcelo Tosatti
2006-03-23 18:15 ` Linus Torvalds
2006-03-23 18:26 ` Rik van Riel
2006-03-23 18:48 ` Diego Calleja
2006-03-23 19:03 ` Peter Zijlstra
2006-03-23 22:30 ` Marcelo Tosatti
2006-03-23 20:49 ` Linus Torvalds [this message]
2006-03-23 20:59 ` Rik van Riel
2006-03-24 15:06 ` Helge Hafting
2006-03-28 23:05 ` Elladan
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