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From: "H. Peter Anvin" <hpa@zytor.com>
To: Alex Elsayed <eternaleye@gmail.com>
Cc: linux-raid@vger.kernel.org, linux-btrfs@vger.kernel.org
Subject: Re: [PATCH 1/4] md: Factor out RAID6 algorithms into lib/
Date: Wed, 29 Jul 2009 11:20:58 -0700	[thread overview]
Message-ID: <4A70930A.1050006@zytor.com> (raw)
In-Reply-To: <h3t5lm$2n2$2@ger.gmane.org>

On 07/18/2009 11:52 AM, Alex Elsayed wrote:
> Alex Elsayed wrote:
> 
>> H. Peter Anvin wrote:
>>> implementation in Java, called "Jerasure".)  Implementability using real 
>>> array instruction sets is key to decent performance.
>> Actually, it is made clear in the paper that Jerasure is written as a C 
>> library, and Clearsafe is the only Java implementation. Don't let the name 
>> fool you. ;D
> And again, I make a typo. s/Clearsafe/Cleversafe/.
> 

It's still their own implementation of poor quality.  That it is poor
quality shows in the numbers, which are dramatically lower than the
actual Linux implementation -- by an order of magnitude or more.  In
other words, they build a strawman and knock it down.

The actual Linux implementation blasts any of the numbers they have in
their paper, which I presume means they haven't optimized any of them.
As such, all the numbers are meaningless.

	-hpa


  reply	other threads:[~2009-07-29 18:20 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-07-13 14:11 [PATCH 1/4] md: Factor out RAID6 algorithms into lib/ David Woodhouse
2009-07-15 19:23 ` Dan Williams
2009-07-15 20:16   ` Chris Mason
2009-07-15 22:11     ` Dan Williams
2009-07-15 22:11       ` Dan Williams
2009-07-16 17:38   ` H. Peter Anvin
2009-07-17 14:22     ` Ric Wheeler
2009-07-17 15:20       ` H. Peter Anvin
2009-07-17 15:35         ` Ric Wheeler
2009-07-17 15:40           ` H. Peter Anvin
2009-07-17 15:47             ` Ric Wheeler
2009-07-17 15:49               ` H. Peter Anvin
2009-07-17 15:58                 ` Ric Wheeler
2009-07-17 18:59                   ` Alex Elsayed
2009-07-17 19:02                     ` Alex Elsayed
2009-07-29 18:16                       ` H. Peter Anvin
2009-07-17 19:12                 ` Gregory Maxwell
2009-07-17 19:12                   ` Gregory Maxwell
2009-07-18 11:53                 ` David Woodhouse
2009-07-18 11:53                   ` David Woodhouse
2009-07-18 12:45                   ` H. Peter Anvin
2009-07-18 12:45                     ` H. Peter Anvin
2009-07-18 18:50                     ` Alex Elsayed
2009-07-18 18:52                       ` Alex Elsayed
2009-07-29 18:20                         ` H. Peter Anvin [this message]
2009-07-18 12:49                   ` Ric Wheeler
2009-07-18 12:49                     ` Ric Wheeler
2009-07-18 16:26                   ` Dan Williams
2009-07-18 16:26                     ` Dan Williams
2009-07-18 18:42                     ` David Woodhouse
2009-07-18 20:04                       ` Dan Williams
2009-07-19 18:04                         ` David Woodhouse
2009-07-20  5:21                           ` H. Peter Anvin
2009-07-17 15:51               ` H. Peter Anvin

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