From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ric Wheeler Subject: Re: [PATCH 1/4] md: Factor out RAID6 algorithms into lib/ Date: Fri, 17 Jul 2009 10:22:11 -0400 Message-ID: <4A608913.1060808@redhat.com> References: <1247494302.19180.268.camel@macbook.infradead.org> <4A5F6590.9000006@zytor.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4A5F6590.9000006@zytor.com> Sender: linux-raid-owner@vger.kernel.org To: "H. Peter Anvin" Cc: Dan Williams , David Woodhouse , chris.mason@oracle.com, linux-btrfs@vger.kernel.org, neilb@suse.de, linux-raid@vger.kernel.org List-Id: linux-raid.ids On 07/16/2009 01:38 PM, H. Peter Anvin wrote: > Dan Williams wrote: >> On Mon, Jul 13, 2009 at 7:11 AM, David Woodhouse >> wrote: >>> We'll want to use these in btrfs too. >>> >>> Signed-off-by: David Woodhouse >> >> Do you suspect that btrfs will also want to perform these operations >> asynchronously? I am preparing an updated release of the raid6 >> offload patch kit, but the previous WIP release can be browsed at: >> >> http://git.kernel.org/?p=linux/kernel/git/djbw/async_tx.git;a=shortlog;h=raid6 >> >> >> The routines are housed in crypto/async_tx/async_pq.c and >> crypto/async_tx/async_raid6_recov.c. >> >> I also wonder if the raid6 algos are a better fit under crypto/ >> alongside xor? >> > > I am also sitting on a set of synchronous (CPU) acceleration patches > for RAID-6 recovery, just waiting for the APIs to stabilize. > > -hpa > Worth sharing a pointer to a really neat set of papers that describe open source friendly RAID6 and erasure encoding algorithms that were presented last year and this at FAST: http://www.cs.utk.edu/~plank/plank/papers/papers.html If I remember correctly, James Plank's papers also have implemented and benchmarked the various encodings, Ric