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From: "H. Peter Anvin" <hpa@zytor.com>
To: Ilya Yanok <yanok@emcraft.com>
Cc: "H. Peter Anvin" <h.peter.anvin@intel.com>,
	"Williams, Dan J" <dan.j.williams@intel.com>,
	"linux-raid@vger.kernel.org" <linux-raid@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"neilb@suse.de" <neilb@suse.de>,
	"Sosnowski, Maciej" <maciej.sosnowski@intel.com>,
	Yuri Tikhonov <yur@emcraft.com>
Subject: Re: [PATCH 06/13] async_tx: add support for asynchronous GF 	multiplication
Date: Fri, 20 Mar 2009 19:30:49 -0700	[thread overview]
Message-ID: <49C45159.8020503@zytor.com> (raw)
In-Reply-To: <49C42F99.5010700@emcraft.com>

Ilya Yanok wrote:
> 
> async_gen_syndrome() takes element of GF^n(256) and returns result of
> scalar multiplication of it with constant ({01}, {02}, {02}^2, ...,
> {02}^n) vector.

For any n (which would mean any GF field)?  In that case, that is
generic scalar-vector multiplication...

> async_pq() takes two vectors from GF^n(256) and returns their scalar
> multiplication.
> 
> We need async_pq() function if we want to offload D_x = A * (P + P_{xy})
> + B * (Q + Q_{xy}) part of DD recovery and D_x = (Q + Q_x) * g^{-x} part
> of DP recovery.


No, you don't.  A and B (and g^{-x}) are scalars, meaning they're the
same for every element.  This is simpler to do.

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.


  reply	other threads:[~2009-03-21  2:30 UTC|newest]

Thread overview: 58+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-03-18 19:20 [PATCH 00/13] Asynchronous raid6 acceleration (part 1 of 2) Dan Williams
2009-03-18 19:20 ` [PATCH 01/13] md/raid6: move raid6 data processing to raid6_pq.ko Dan Williams
2009-03-19 20:09   ` Andre Noll
2009-03-22 17:22     ` Dan Williams
2009-03-22 17:22       ` Dan Williams
2009-03-18 19:20 ` [PATCH 02/13] async_tx: don't use src_list argument of async_xor() for dma addresses Dan Williams
2009-03-19 20:10   ` Andre Noll
2009-03-25 17:11     ` Dan Williams
2009-03-25 17:11       ` Dan Williams
2009-03-26 10:39       ` Andre Noll
2009-03-18 19:20 ` [PATCH 03/13] async_tx: provide __async_inline for HAS_DMA=n archs Dan Williams
2009-03-18 19:20 ` [PATCH 04/13] async_tx: kill needless module_{init|exit} Dan Williams
2009-03-18 19:20 ` [PATCH 05/13] async_tx: add sum check flags Dan Williams
2009-03-18 19:20 ` [PATCH 06/13] async_tx: add support for asynchronous GF multiplication Dan Williams
2009-03-19 16:06   ` H. Peter Anvin
2009-03-19 17:20     ` Dan Williams
2009-03-19 17:20       ` Dan Williams
2009-03-20 22:43       ` H. Peter Anvin
2009-03-20 23:00         ` Ilya Yanok
2009-03-20 23:25           ` H. Peter Anvin
2009-03-21  0:06             ` Ilya Yanok
2009-03-21  2:30               ` H. Peter Anvin [this message]
2009-03-21 10:19                 ` Ilya Yanok
2009-03-21 19:16                   ` H. Peter Anvin
2009-03-21 15:19                 ` Dan Williams
2009-03-21 15:19                   ` Dan Williams
2009-03-21 19:15                   ` H. Peter Anvin
2009-03-21 22:14                     ` Dan Williams
2009-03-21 22:14                       ` Dan Williams
2009-03-21 22:26                       ` Ilya Yanok
2009-03-21 22:46                         ` Dan Williams
2009-03-21 22:46                           ` Dan Williams
2009-03-21 20:05     ` Ilya Yanok
2009-03-21 22:00       ` Dan Williams
2009-03-21 22:00         ` Dan Williams
2009-03-21 22:43         ` Ilya Yanok
2009-03-21 22:53           ` Dan Williams
2009-03-21 22:53             ` Dan Williams
2009-03-22 21:37             ` Ilya Yanok
2009-03-19 20:09   ` Andre Noll
2009-03-30 14:30   ` Sosnowski, Maciej
2009-03-18 19:20 ` [PATCH 07/13] async_tx: add support for asynchronous RAID6 recovery operations Dan Williams
2009-03-23 10:11   ` Andre Noll
2009-03-30 14:30   ` Sosnowski, Maciej
2009-03-18 19:20 ` [PATCH 08/13] iop-adma: P+Q support for iop13xx adma engines Dan Williams
2009-03-18 19:21 ` [PATCH 09/13] iop-adma: P+Q self test Dan Williams
2009-03-20  0:14   ` Neil Brown
2009-03-20  0:19     ` Dan Williams
2009-03-20  0:19       ` Dan Williams
2009-03-30 14:30   ` Sosnowski, Maciej
2009-03-18 19:21 ` [PATCH 10/13] dmaengine: allow dma support for async_tx to be toggled Dan Williams
2009-03-18 19:21 ` [PATCH 11/13] dmatest: add xor test Dan Williams
2009-03-18 19:21 ` [PATCH 12/13] dmatest: add dma interrupts and callbacks Dan Williams
2009-03-18 19:21 ` [PATCH 13/13] dmatest: add pq support Dan Williams
2009-03-18 23:43 ` [PATCH 00/13] Asynchronous raid6 acceleration (part 1 of 2) Andi Kleen
2009-03-19 17:08   ` Dan Williams
2009-03-19 17:08     ` Dan Williams
2009-03-20  0:30 ` Neil Brown

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