From: Eric Rannaud <eric.rannaud@gmail.com>
To: Valdis.Kletnieks@vt.edu
Cc: Jonathan Corbet <corbet@lwn.net>, Izik Eidus <ieidus@redhat.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
kvm@vger.kernel.org, aarcange@redhat.com, chrisw@redhat.com,
avi@redhat.com
Subject: Re: [PATCH 3/4] add ksm kernel shared memory driver
Date: Wed, 12 Nov 2008 22:13:47 -0800 [thread overview]
Message-ID: <1226556827.13670.54.camel@nc050> (raw)
In-Reply-To: <23027.1226443216@turing-police.cc.vt.edu>
On Tue, 2008-11-11 at 17:40 -0500, Valdis.Kletnieks@vt.edu wrote:
> On Tue, 11 Nov 2008 15:03:45 MST, Jonathan Corbet said:
> Seems reasonably sane to me - only doing the first 128 bytes rather than
> a full 4K page is some 32 times faster. Yes, you'll have the *occasional*
> case where two pages were identical for 128 bytes but then differed, which is
> why there's buckets. But the vast majority of the time, at least one bit
> will be different in the first part.
In the same spirit, computing a CRC32 instead of a SHA1 would probably
be faster as well (faster to compute, and faster to compare the
digests). The increased rate of collision should be negligible.
Also, the upcoming SSE4.2 (Core i7) has a CRC32 instruction. (Support is
already in the kernel: arch/x86/crypto/crc32c-intel.c)
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next prev parent reply other threads:[~2008-11-13 6:13 UTC|newest]
Thread overview: 79+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-11-11 13:21 [PATCH 0/4] ksm - dynamic page sharing driver for linux Izik Eidus
2008-11-11 13:21 ` [PATCH 1/4] rmap: add page_wrprotect() function, Izik Eidus, Izik Eidus
2008-11-11 13:21 ` [PATCH 2/4] Add replace_page(), change the mapping of pte from one page into another Izik Eidus, Izik Eidus
2008-11-11 13:21 ` [PATCH 3/4] add ksm kernel shared memory driver Izik Eidus, Izik Eidus
2008-11-11 13:21 ` [PATCH 4/4] MMU_NOTIFIRES: add set_pte_at_notify() Izik Eidus, Izik Eidus
2008-11-11 20:38 ` [PATCH 3/4] add ksm kernel shared memory driver Andrew Morton
2008-11-11 22:03 ` Andrea Arcangeli
2008-11-11 22:03 ` Jonathan Corbet
2008-11-11 22:17 ` Izik Eidus
2008-11-11 22:25 ` Jonathan Corbet
2008-11-11 22:31 ` Izik Eidus
2008-11-11 22:30 ` Jonathan Corbet
2008-11-11 22:38 ` Izik Eidus
2008-11-11 23:02 ` Izik Eidus
2008-11-11 23:03 ` Andrea Arcangeli
2008-11-11 22:49 ` Avi Kivity
2008-11-11 22:40 ` Valdis.Kletnieks
2008-11-13 6:13 ` Eric Rannaud [this message]
2008-11-11 22:43 ` Avi Kivity
2008-11-11 19:45 ` [PATCH 2/4] Add replace_page(), change the mapping of pte from one page into another Andrew Morton
2008-11-11 20:57 ` Izik Eidus
2008-11-11 21:21 ` Christoph Lameter
2008-11-11 21:23 ` Izik Eidus
2008-11-11 21:31 ` Christoph Lameter
2008-11-11 21:37 ` Izik Eidus
2008-11-11 22:24 ` Andrea Arcangeli
2008-11-12 2:19 ` KAMEZAWA Hiroyuki
2008-11-12 10:05 ` Avi Kivity
2008-11-12 11:11 ` Izik Eidus
2008-11-13 6:11 ` KAMEZAWA Hiroyuki
2008-11-13 10:38 ` Izik Eidus
2008-11-13 11:32 ` KAMEZAWA Hiroyuki
2008-11-11 21:35 ` Andrea Arcangeli
2008-11-11 21:06 ` Andrea Arcangeli
2008-11-11 21:26 ` Christoph Lameter
2008-11-11 21:39 ` Avi Kivity
2008-11-11 21:47 ` Christoph Lameter
2008-11-11 21:55 ` Izik Eidus
2008-11-11 22:36 ` Avi Kivity
2008-11-11 22:17 ` Andrea Arcangeli
2008-11-11 22:30 ` Christoph Lameter
2008-11-11 23:17 ` Andrea Arcangeli
2008-11-11 23:25 ` Andrea Arcangeli
2008-11-12 0:27 ` Christoph Lameter
2008-11-12 2:27 ` Andrea Arcangeli
2008-11-12 3:10 ` Christoph Lameter
2008-11-12 17:32 ` Andrea Arcangeli
2008-11-12 20:08 ` Lee Schermerhorn
2008-11-12 20:31 ` Christoph Lameter
2008-11-12 20:27 ` Christoph Lameter
2008-11-12 22:09 ` Lee Schermerhorn
2008-11-13 2:00 ` Andrea Arcangeli
2008-11-13 2:31 ` Andrea Arcangeli
2008-11-13 4:02 ` Nick Piggin
2008-11-11 19:39 ` [PATCH 1/4] rmap: add page_wrprotect() function, Andrew Morton
2008-11-11 20:38 ` Andrea Arcangeli
2008-11-11 21:01 ` Andrew Morton
2008-11-11 21:17 ` Andrea Arcangeli
2008-11-11 18:30 ` [PATCH 0/4] ksm - dynamic page sharing driver for linux Andrew Morton
2008-11-11 18:48 ` Avi Kivity
2008-11-11 19:08 ` Izik Eidus
2008-11-11 19:11 ` Andrew Morton
2008-11-11 19:18 ` Izik Eidus
2008-11-11 19:32 ` Andrew Morton
2008-11-11 19:52 ` Izik Eidus
2008-11-11 20:08 ` Izik Eidus
2008-11-11 19:29 ` Avi Kivity
2008-11-11 19:55 ` Andrea Arcangeli
2008-11-11 19:07 ` Izik Eidus
2008-11-11 19:20 ` Andrew Morton
-- strict thread matches above, loose matches on Subject: below --
2008-11-17 2:20 [PATCH 0/4] ksm - dynamic page sharing driver for linux v2 Izik Eidus
2008-11-17 2:20 ` [PATCH 1/4] Rmap: Add page_wrprotect() function Izik Eidus
2008-11-17 2:20 ` [PATCH 2/4] Add replace_page(): change the page pte is pointing to Izik Eidus
2008-11-17 2:20 ` [PATCH 3/4] add ksm kernel shared memory driver Izik Eidus
2008-11-28 16:58 ` Alan Cox
2008-12-02 18:07 ` Chris Wright
2008-12-02 18:13 ` Alan Cox
2008-12-02 21:24 ` Chris Wright
2008-12-02 21:37 ` Jonathan Corbet
2008-12-02 22:10 ` Alan Cox
2008-12-03 14:33 ` Pavel Machek
2008-12-04 9:48 ` Alan Cox
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