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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 12:08:36 -0800	[thread overview]
Message-ID: <m5ihs4$cep$2@ger.gmane.org> (raw)
In-Reply-To: m5ihkj$cep$1@ger.gmane.org

Alex Elsayed wrote:

> John Williams wrote:
>> Again, irrelevant. The Spooky2, CityHash256, and Murmur3 hashes that I
>> am talking about can and do take advantage of CPU architecture. For
>> 128- and 256-bit hashes, one (or more) of those three will be
>> significantly faster than any crypto hash in the Crypto API,
>> regardless of the CPU it is run on.
> 
> Sure.

Actually, I said "Sure" here, but this isn't strictly true. At some point, 
you're more memory-bound than CPU-bound, and with CPU intrinsic instructions 
(like SPARC and recent x86 have for SHA) you're often past that. Then, 
you're not going to see any real difference - and the accelerated 
cryptographic hashes may even win out, because the intrinsics may be faster 
(less stuff of the I$, pipelined single instruction beating multiple simpler 
instructions, etc) than the software non-cryptographic hash.


  reply	other threads:[~2014-12-01 20:10 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 [this message]
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
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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