From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org (bilbo.ozlabs.org [103.22.144.67]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 404rD91XmbzF1W6 for ; Tue, 20 Mar 2018 09:22:49 +1100 (AEDT) In-Reply-To: <20170804034233.13628-1-matthew.brown.dev@gmail.com> To: Matt Brown , linuxppc-dev@lists.ozlabs.org From: Michael Ellerman Cc: dja@axtens.net Subject: Re: [v6, 1/2] raid6/altivec: Add vpermxor implementation for raid6 Q syndrome Message-Id: <404rD729Rpz9sVr@ozlabs.org> Date: Tue, 20 Mar 2018 09:22:46 +1100 (AEDT) List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Fri, 2017-08-04 at 03:42:32 UTC, Matt Brown wrote: > This patch uses the vpermxor instruction to optimise the raid6 Q syndrome. > This instruction was made available with POWER8, ISA version 2.07. > It allows for both vperm and vxor instructions to be done in a single > instruction. This has been tested for correctness on a ppc64le vm with a > basic RAID6 setup containing 5 drives. > > The performance benchmarks are from the raid6test in the /lib/raid6/test > directory. These results are from an IBM Firestone machine with ppc64le > architecture. The benchmark results show a 35% speed increase over the best > existing algorithm for powerpc (altivec). The raid6test has also been run > on a big-endian ppc64 vm to ensure it also works for big-endian > architectures. > > Performance benchmarks: > raid6: altivecx4 gen() 18773 MB/s > raid6: altivecx8 gen() 19438 MB/s > > raid6: vpermxor4 gen() 25112 MB/s > raid6: vpermxor8 gen() 26279 MB/s > > Signed-off-by: Matt Brown > Reviewed-by: Daniel Axtens Series applied to powerpc next, thanks. https://git.kernel.org/powerpc/c/2de95953c4e6ad54c9bee5e6a5518d cheers