From mboxrd@z Thu Jan 1 00:00:00 1970 From: Linus Torvalds Subject: Re: [PATCH] block-sha1: more good unaligned memory access candidates Date: Thu, 13 Aug 2009 12:54:06 -0700 (PDT) Message-ID: References: <7v63crbja2.fsf@alter.siamese.dyndns.org> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Cc: Nicolas Pitre , git@vger.kernel.org To: Junio C Hamano X-From: git-owner@vger.kernel.org Thu Aug 13 21:57:23 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 1MbgQN-0004wH-5f for gcvg-git-2@gmane.org; Thu, 13 Aug 2009 21:57:23 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755544AbZHMTyv (ORCPT ); Thu, 13 Aug 2009 15:54:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755518AbZHMTyu (ORCPT ); Thu, 13 Aug 2009 15:54:50 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:32877 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754262AbZHMTyt (ORCPT ); Thu, 13 Aug 2009 15:54:49 -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 n7DJs6ii023017 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Thu, 13 Aug 2009 12:54:07 -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 n7DJs6Q3007642; Thu, 13 Aug 2009 12:54:06 -0700 X-X-Sender: torvalds@localhost.localdomain In-Reply-To: <7v63crbja2.fsf@alter.siamese.dyndns.org> User-Agent: Alpine 2.01 (LFD 1184 2008-12-16) X-Spam-Status: No, hits=-5.463 required=5 tests=AWL,BAYES_00,OSDL_HEADER_SUBJECT_BRACKETED,PATCH_SUBJECT_OSDL 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, 13 Aug 2009, Junio C Hamano wrote: > > Wow. Is it now faster than the arm/ and ppc/ hand-tweaked assembly? For the good cases, yes. For POWER, with gcc-4.4, the C code apparently outperforms the asm code on POWER6. The asm code is scheduled for POWER4, and I think outperforms the C code there. Also, when compiling in 64-bit mode (with "-m64"), at least some versions of gcc seem to do some stupid things and add extra zero extension stuff, and that performed suboptimally at least on a PPC G5. So it's certainly not a clear case of "the C code outperforms the asm code", but in BenH's tests, the best numbers really did come from the C version. With some silly cases of at least some versions gcc screwing up (not reload, but zero extension), and making it noticeably slower. IOW, the PPC situation really isn't that different from x86. Linus