From: Alex Elsayed <eternaleye@gmail.com>
To: linux-btrfs@vger.kernel.org
Subject: Re: [RFC PATCH] Btrfs: add sha256 checksum option
Date: Mon, 01 Dec 2014 16:34:16 -0800 [thread overview]
Message-ID: <m5j1e8$5jk$1@ger.gmane.org> (raw)
In-Reply-To: CAJBj3vd83Vgfxsfitbz0vVma-jPWb22nj=PC-kigxnipV=BrKA@mail.gmail.com
John Williams wrote:
> On Mon, Dec 1, 2014 at 4:15 PM, Alex Elsayed <eternaleye@gmail.com> wrote:
>> There's a thing called the transitive property. When CRC32 is faster than
>> SpookyHash and CityHash (while admittedly weaker), and SHA-1 on SPARC is
>> faster than CRC32, there are comparisons that can be made.
>
> And yet you applied the transitive property with poor assumptions and
> in a convoluted way to come up with an incorrect conclusion.
>
>
>> It's that the flat assertion that "CityHash/SpookyHash/etc is always
>> faster" is _unwarranted_, as hardware acceleration _has a huge effect_.
>
> Actually, the assertion is true and backed up by evidence that I
> cited. I'm not sure why you think hardware acceleration only helps
> SHA-1 and does not help CityHash or SpookyHash.
...because the hardware acceleration is in the form of instructions like
"Update SHA1 state" ?
https://software.intel.com/en-us/articles/intel-sha-extensions
https://www.element14.com/community/servlet/JiveServlet/previewBody/41836-102-1-229511/ARM.Reference_Manual.pdf
(page 99, the SHA1{C,P,M,H,SU0,SU1} instructions)
On SPARC it's a full-on crypto coprocessor.
next prev parent reply other threads:[~2014-12-02 0:34 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-24 5:23 [RFC PATCH] Btrfs: add sha256 checksum option Liu Bo
2014-11-24 5:23 ` [RFC PATCH] Btrfs-progs: support sha256 checksum algorithm Liu Bo
2014-11-24 8:23 ` [RFC PATCH] Btrfs: add sha256 checksum option Holger Hoffstätte
2014-11-24 18:55 ` Duncan
2014-11-24 19:34 ` John Williams
2014-11-25 10:30 ` Liu Bo
2014-11-25 10:52 ` Daniel Cegiełka
2014-11-25 23:17 ` John Williams
2014-11-26 12:50 ` Holger Hoffstätte
2014-11-26 17:53 ` John Williams
2014-11-25 10:28 ` Liu Bo
2014-11-24 20:07 ` Chris Mason
2014-11-24 20:58 ` Hugo Mills
2014-11-25 3:04 ` Qu Wenruo
2014-11-25 5:13 ` Zygo Blaxell
2014-11-25 11:30 ` Liu Bo
2014-11-26 13:36 ` Brendan Hide
2014-11-25 16:47 ` David Sterba
2014-11-25 19:45 ` Bardur Arantsson
2014-11-26 13:38 ` Brendan Hide
2014-11-26 13:58 ` Austin S Hemmelgarn
2014-12-01 18:37 ` David Sterba
2014-12-01 20:35 ` Austin S Hemmelgarn
2014-12-01 20:51 ` John Williams
2014-12-01 23:23 ` Alex Elsayed
2014-12-15 18:47 ` David Sterba
2014-11-25 16:39 ` David Sterba
2014-11-27 3:52 ` Liu Bo
2014-12-01 18:51 ` David Sterba
2014-11-29 20:38 ` Alex Elsayed
2014-11-29 21:00 ` John Williams
2014-11-29 21:07 ` Alex Elsayed
2014-11-29 21:21 ` John Williams
2014-11-29 21:27 ` Alex Elsayed
2014-12-01 12:39 ` Austin S Hemmelgarn
2014-12-01 17:22 ` John Williams
2014-12-01 17:42 ` Austin S Hemmelgarn
2014-12-01 17:49 ` John Williams
2014-12-01 19:28 ` Alex Elsayed
2014-12-01 19:34 ` Alex Elsayed
2014-12-01 20:26 ` Austin S Hemmelgarn
2014-12-01 19:58 ` John Williams
2014-12-01 20:04 ` Alex Elsayed
2014-12-01 20:08 ` Alex Elsayed
2014-12-01 20:46 ` John Williams
2014-12-01 22:56 ` Alex Elsayed
2014-12-01 23:05 ` Alex Elsayed
2014-12-01 23:37 ` John Williams
2014-12-01 23:46 ` Alex Elsayed
2014-12-02 0:03 ` John Williams
2014-12-02 0:15 ` Alex Elsayed
2014-12-02 0:30 ` John Williams
2014-12-02 0:34 ` Alex Elsayed [this message]
2014-12-02 0:11 ` John Williams
2014-12-01 23:48 ` John Williams
2014-12-02 0:06 ` Alex Elsayed
2014-12-02 0:10 ` Alex Elsayed
2014-12-02 0:16 ` John Williams
2014-12-02 0:28 ` Christoph Anton Mitterer
2014-12-02 0:43 ` Alex Elsayed
2014-12-02 0:53 ` Christoph Anton Mitterer
2014-12-02 1:25 ` Alex Elsayed
2014-12-02 1:32 ` Alex Elsayed
2014-11-30 22:51 ` Christoph Anton Mitterer
2014-11-30 22:59 ` Christoph Anton Mitterer
2014-11-30 23:05 ` Dimitri John Ledkov
2014-12-01 2:55 ` Christoph Anton Mitterer
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