From: "Darrick J. Wong" <djwong@us.ibm.com>
To: Joakim Tjernlund <joakim.tjernlund@transmode.se>
Cc: "'Andreas Dilger'" <adilger.kernel@dilger.ca>,
"'Andrew Morton'" <akpm@linux-foundation.org>,
"'Mingming Cao'" <cmm@us.ibm.com>,
"'Herbert Xu'" <herbert@gondor.apana.org.au>,
"'linux-crypto'" <linux-crypto@vger.kernel.org>,
linux-ext4@vger.kernel.org,
"'linux-fsdevel'" <linux-fsdevel@vger.kernel.org>,
"'linux-kernel'" <linux-kernel@vger.kernel.org>,
Bob Pearson <rpearson@systemfabricworks.com>,
"'Theodore Tso'" <tytso@mit.edu>
Subject: Re: [PATCH 14/14] crc32: Select an algorithm via kconfig
Date: Tue, 13 Dec 2011 10:36:44 -0800 [thread overview]
Message-ID: <20111213183644.GO7137@tux1.beaverton.ibm.com> (raw)
In-Reply-To: <OF62576D22.A1ACD2B5-ONC1257965.002E3817-C1257965.002E6F16@transmode.se>
On Tue, Dec 13, 2011 at 09:27:10AM +0100, Joakim Tjernlund wrote:
> "Darrick J. Wong" <djwong@us.ibm.com> wrote on 2011/12/13 07:32:28:
> >
> > On Mon, Dec 12, 2011 at 05:10:45PM -0600, Bob Pearson wrote:
> > > That choice was for Joakim who measured better performance on his 32 bit PPC
> > > platform with "by 4".
> >
> > Ok. On my 1.33GHz PowerBook I get ~255MB/s with slice by 4 and ~270MB/s with
> > slice by 8. I think it's a PPC 7447, and definitely 32-bit. In any case, it
> > reports having 32K of L1D cache.
>
> I tested Bobs early version on my mpc8321(266MHz, embedded CPU) and it was just
> half the speed compared with current crc32.
I wonder, given the patch "crc32: Speed up memory table access on powerpc"
would you mind retesting to see if slice by 8 still trails slice by 4 on your
powerpc? I see that your mpc8321 has 16K of L1D cache and a 32-bit memory bus
whereas my 7447 has a 64-bit memory bus. I wonder if memory bus size could be
a defining characteristic...?
I tried it out the crc32c code on a s390x today; apparently by-8 trails by-4
there too. It's unfortunately difficult to figure out the hardware details of
whatever's going on underneath that VM.
--D
>
> Jocke
>
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next prev parent reply other threads:[~2011-12-13 18:36 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-01 20:13 [PATCH v5.2 00/14] crc32c: Add faster algorithm and self-test code Darrick J. Wong
2011-12-01 20:13 ` [PATCH 01/14] crc32: removed two instances of trailing whitespaces Darrick J. Wong
2011-12-01 20:13 ` [PATCH 02/14] crc32: Move long comment about crc32 fundamentals to Documentation/ Darrick J. Wong
2011-12-01 20:14 ` [PATCH 03/14] crc32: Simplify unit test code Darrick J. Wong
2011-12-01 20:14 ` [PATCH 04/14] crc32: Speed up memory table access on powerpc Darrick J. Wong
2011-12-01 20:14 ` [PATCH 05/14] crc32: Miscellaneous cleanups Darrick J. Wong
2011-12-01 20:14 ` [PATCH 06/14] crc32: Fix mixing of endian-specific types Darrick J. Wong
2011-12-01 20:14 ` [PATCH 07/14] crc32: Make CRC_*_BITS definition correspond to actual bit counts Darrick J. Wong
2011-12-01 20:14 ` [PATCH 08/14] crc32: Add slice-by-8 algorithm to existing code Darrick J. Wong
2011-12-01 20:14 ` [PATCH 09/14] crc32: Optimize loop counter for x86 Darrick J. Wong
2011-12-01 20:14 ` [PATCH 10/14] crc32: Add note about this patchset to crc32.c Darrick J. Wong
2011-12-01 20:14 ` [PATCH 11/14] crc32: Bolt on crc32c Darrick J. Wong
2011-12-01 20:15 ` [PATCH 12/14] crypto: crc32c should use library implementation Darrick J. Wong
2011-12-01 20:15 ` [PATCH 13/14] crc32: Add self-test code for crc32c Darrick J. Wong
2011-12-01 20:15 ` [PATCH 14/14] crc32: Select an algorithm via kconfig Darrick J. Wong
2011-12-02 0:25 ` Herbert Xu
2011-12-03 2:36 ` Darrick J. Wong
2011-12-12 22:58 ` Darrick J. Wong
2011-12-12 23:10 ` Bob Pearson
2011-12-13 6:32 ` Darrick J. Wong
2011-12-13 8:27 ` Joakim Tjernlund
2011-12-13 18:36 ` Darrick J. Wong [this message]
2011-12-01 20:20 ` [PATCH v5.2 00/14] crc32c: Add faster algorithm and self-test code Joel Becker
2011-12-01 20:31 ` Darrick J. Wong
2011-12-02 0:23 ` Herbert Xu
2011-12-03 2:30 ` Darrick J. Wong
2011-12-03 11:00 ` Herbert Xu
-- strict thread matches above, loose matches on Subject: below --
2012-01-07 5:50 [PATCH v5.3 " Darrick J. Wong
2012-01-07 5:52 ` [PATCH 14/14] crc32: Select an algorithm via kconfig Darrick J. Wong
2011-11-28 22:36 [PATCH v5.1 00/14] crc32c: Add faster algorithm and self-test code Darrick J. Wong
2011-11-28 22:38 ` [PATCH 14/14] crc32: Select an algorithm via kconfig Darrick J. Wong
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