From mboxrd@z Thu Jan 1 00:00:00 1970 From: Linus Torvalds Subject: Re: [PATCH 0/7] block-sha1: improved SHA1 hashing Date: Thu, 6 Aug 2009 13:53:11 -0700 (PDT) Message-ID: References: <4A7B1166.8020507@gmail.com> <4A7B2A88.2040602@gmail.com> <4A7B384C.2020407@gmail.com> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Cc: Git Mailing List To: Artur Skawina X-From: git-owner@vger.kernel.org Thu Aug 06 22:53:40 2009 Return-path: Envelope-to: gcvg-git-2@gmane.org Received: from vger.kernel.org ([209.132.176.167]) by lo.gmane.org with esmtp (Exim 4.50) id 1MZ9xz-00032k-PB for gcvg-git-2@gmane.org; Thu, 06 Aug 2009 22:53:40 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756224AbZHFUxb (ORCPT ); Thu, 6 Aug 2009 16:53:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756181AbZHFUxb (ORCPT ); Thu, 6 Aug 2009 16:53:31 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:38604 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755955AbZHFUxa (ORCPT ); Thu, 6 Aug 2009 16:53:30 -0400 Received: from imap1.linux-foundation.org (imap1.linux-foundation.org [140.211.169.55]) by smtp1.linux-foundation.org (8.14.2/8.13.5/Debian-3ubuntu1.1) with ESMTP id n76KrBrS005622 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Thu, 6 Aug 2009 13:53:12 -0700 Received: from localhost (localhost [127.0.0.1]) by imap1.linux-foundation.org (8.13.5.20060308/8.13.5/Debian-3ubuntu1.1) with ESMTP id n76KrBdv008966; Thu, 6 Aug 2009 13:53:11 -0700 X-X-Sender: torvalds@localhost.localdomain In-Reply-To: <4A7B384C.2020407@gmail.com> User-Agent: Alpine 2.01 (LFD 1184 2008-12-16) X-Spam-Status: No, hits=-3.966 required=5 tests=AWL,BAYES_00,OSDL_HEADER_SUBJECT_BRACKETED X-Spam-Checker-Version: SpamAssassin 3.2.4-osdl_revision__1.47__ X-MIMEDefang-Filter: lf$Revision: 1.188 $ X-Scanned-By: MIMEDefang 2.63 on 140.211.169.13 Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: On Thu, 6 Aug 2009, Artur Skawina wrote: > > it's a bit slower (P4): > > before: linus 0.6288 97.06 > after: linus 0.6604 92.42 Hmm. Ok, I just tested with your harness, and I get # TIME[s] SPEED[MB/s] rfc3174 5.1 119.7 rfc3174 5.097 119.7 linus 1.836 332.5 linusas 2.006 304.3 linusas2 1.879 324.9 mozilla 5.562 109.7 mozillaas 5.913 103.2 openssl 1.613 378.5 spelvin 1.698 359.5 spelvina 1.602 381 nettle 1.594 382.9 with it, so it is faster for me. So your slowdown seems to be yet another P4 thing. Dang crazy micro-architecture. Of course, it might be a compiler version difference too. I'm using gcc-4.4.0. With the cpp variable renaming, the compiler really has less to be smart about, but spill decisions will still matter a lot. (My old 32-bit numbers were linus 2.092 291.8 so it's a clear improvement on my machine and with my compiler). It also seems to improve the 64-bit numbers a small bit, I'm getting # TIME[s] SPEED[MB/s] rfc3174 3.98 153.3 rfc3174 3.972 153.7 linus 1.514 403.1 linusas 1.555 392.6 linusas2 1.599 381.7 mozilla 4.34 140.6 mozillaas 4.223 144.5 with my 64-bit compile, so on a Nehalem it's the best one of the C ones by a noticeable margin. (My original 64-bit numbers were linus 1.54 396.3 and while the numbers seem to fluctuate a bit, the fluctuation is roughly in the 1% range, so that improvement seems to be statistically significant. Oh, I did make a small change, but I doubt it matters. Instead of doing TEMP += E + SHA_ROL(A,5) + (fn) + (constant); \ B = SHA_ROR(B, 2); E = TEMP; } while (0) I now do E += TEMP + SHA_ROL(A,5) + (fn) + (constant); \ B = SHA_ROR(B, 2); } while (0) which is a bit more logical (the old TEMP usage was just due to a fairly mindless conversion). That _might_ have lower register pressure if the compiler is silly enough to not notice that it can do it. Maybe that matters. Linus