Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755514AbZCUW07 (ORCPT ); Sat, 21 Mar 2009 18:26:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753815AbZCUW0r (ORCPT ); Sat, 21 Mar 2009 18:26:47 -0400 Received: from ocean.emcraft.com ([213.221.7.182]:40031 "EHLO ocean.emcraft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752144AbZCUW0q (ORCPT ); Sat, 21 Mar 2009 18:26:46 -0400 Message-ID: <49C5699C.8050405@emcraft.com> Date: Sun, 22 Mar 2009 01:26:36 +0300 From: Ilya Yanok User-Agent: Mozilla-Thunderbird 2.0.0.19 (X11/20090103) MIME-Version: 1.0 To: Dan Williams CC: "H. Peter Anvin" , "H. Peter Anvin" , "linux-raid@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "neilb@suse.de" , "Sosnowski, Maciej" , Yuri Tikhonov Subject: Re: [PATCH 06/13] async_tx: add support for asynchronous GF multiplication References: <20090318191248.20375.40560.stgit@dwillia2-linux.ch.intel.com> <49C26D91.10804@intel.com> <49C41C1E.4060401@zytor.com> <49C4201A.5060905@emcraft.com> <49C425F5.8060309@intel.com> <49C42F99.5010700@emcraft.com> <49C45159.8020503@zytor.com> <49C53CC0.5060303@zytor.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1244 Lines: 35 Hi Dan, Dan Williams wrote: >> Why does it? I don't see why you'd need to cover the vector-vector case >> at all, since it doesn't appear anywhere in the algorithms. Certainly >> going backwards from a vector-vector set to derive if you can do a >> scalar-vector multiply when you should have known that in the first >> place is not really useful. >> >> >>> Looking closer, the only other caller, async_pq_zero_sum, can be >>> deleted because it has no users. So async_pq can become a static >>> routine in async_r6recov. >>> >>> >> That's another issue entirely, of course :) >> >> > > ...ah, but now I see your point and the root cause of the problem. > The caller needs to be modified to only require scalar multiplication > even in this corner case. > Argh... There is no vector-vector multiplication at all! You just need to swap the 'for' cycles back (as it was in the original patch by me and Yuri) to get rid of two-dimensional lookup at each step. Regards, Ilya. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/