From mboxrd@z Thu Jan 1 00:00:00 1970 From: "H. Peter Anvin" Subject: Re: [PATCH 1/4] md: Factor out RAID6 algorithms into lib/ Date: Fri, 17 Jul 2009 11:51:03 -0400 Message-ID: <4A609DE7.5070002@zytor.com> References: <1247494302.19180.268.camel@macbook.infradead.org> <4A5F6590.9000006@zytor.com> <4A608913.1060808@redhat.com> <4A6096A0.5050501@zytor.com> <4A609A52.7070506@redhat.com> <4A609B72.2010901@zytor.com> <4A609CFA.2060707@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4A609CFA.2060707@redhat.com> Sender: linux-btrfs-owner@vger.kernel.org To: Ric Wheeler 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 Ric Wheeler wrote: >> >> The main flaw, as I said, is in the phrase "as implemented by the >> Jerasure library". He's comparing his own implementations of various >> algorithms, not optimized implementations. >> >> The bottom line is pretty much this: the cost of changing the encoding >> would appear to outweigh the benefit. I'm not trying to claim the Linux >> RAID-6 implementation is optimal, but it is simple and appears to be >> fast enough that the math isn't the bottleneck. > > Cost? Thank about how to get free grad student hours testing out things > that you might or might not want to leverage on down the road :-) > Anyway... I don't really care too much. If someone wants to redesign the Linux RAID-6 and Neil decides to take it I'm not going to object. I'm also not very likely to do any work on it. -hpa