From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Bob Pearson" Subject: RE: [patch 37/44] rxe_sb8.c Date: Fri, 1 Jul 2011 18:09:10 -0500 Message-ID: <000601cc3843$e3854cb0$aa8fe610$@systemfabricworks.com> References: <20110701131821.928693424@systemfabricworks.com> <20110701132202.486466900@systemfabricworks.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Content-Language: en-us Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: 'Roland Dreier' Cc: linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-rdma@vger.kernel.org Hi Roland, Perhaps. We have some ICRC specific APIs as well as plain Jane CRC calculation that includes a copy at the same time. If I knew who maintained crc32.c I would be happy to talk to them and see what they think. The reason I wrote this Is that crc32.c takes about 6 clocks per byte and this one takes < 2 clocks per byte. We couldn't get over 200-300 MB/sec With crc32.c and this algorithm was hitting 900MB/sec. Sandy Bridge has a generic CRC instruction that should be able to Reduce the time to nothing on top of a copy I have heard. Bob -----Original Message----- From: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org [mailto:linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org] On Behalf Of Roland Dreier Sent: Friday, July 01, 2011 5:04 PM To: rpearson-klaOcWyJdxkshyMvu7JE4pqQE7yCjDx5@public.gmane.org Cc: linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Subject: Re: [patch 37/44] rxe_sb8.c On Fri, Jul 1, 2011 at 6:18 AM, wrote: > Slice by 8 implementation of CRC32. > The code code is similar to the kernel provided crc32 calculation > except runs about 3X faster which allows us to get to ~1GB/sec. Wouldn't the sane thing to do be to fix lib/crc32.c instead? - R. -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html