Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752720AbZFVXIG (ORCPT ); Mon, 22 Jun 2009 19:08:06 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751314AbZFVXHv (ORCPT ); Mon, 22 Jun 2009 19:07:51 -0400 Received: from moutng.kundenserver.de ([212.227.126.187]:63826 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751055AbZFVXHu (ORCPT ); Mon, 22 Jun 2009 19:07:50 -0400 From: Arnd Bergmann To: =?utf-8?q?J=C3=B6rn_Engel?= Subject: Re: [PATCH 06/14] Pramfs: Include files Date: Tue, 23 Jun 2009 01:07:42 +0200 User-Agent: KMail/1.11.90 (Linux/2.6.30-9-generic; KDE/4.2.90; x86_64; ; ) Cc: Chris Simmonds , Marco , Sam Ravnborg , Linux FS Devel , Linux Embedded , Linux Kernel References: <4A33A7EC.6070008@gmail.com> <4A3FDBFE.8050509@2net.co.uk> <20090622214155.GA19332@logfs.org> In-Reply-To: <20090622214155.GA19332@logfs.org> X-Face: I@=L^?./?$U,EK.)V[4*>`zSqm0>65YtkOe>TFD'!aw?7OVv#~5xd\s,[~w]-J!)|%=]> =?utf-8?q?+=0A=09=7EohchhkRGW=3F=7C6=5FqTmkd=5Ft=3FLZC=23Q-=60=2E=60Y=2Ea=5E?= =?utf-8?q?3zb?=) =?utf-8?q?+U-JVN=5DWT=25cw=23=5BYo0=267C=26bL12wWGlZi=0A=09=7EJ=3B=5Cwg?= =?utf-8?q?=3B3zRnz?=,J"CT_)=\H'1/{?SR7GDu?WIopm.HaBG=QYj"NZD_[zrM\Gip^U MIME-Version: 1.0 Content-Type: Text/Plain; charset="utf-8" Content-Transfer-Encoding: 8bit Message-Id: <200906230107.43667.arnd@arndb.de> X-Provags-ID: V01U2FsdGVkX18qbre0CGs2DPIqOSKzNpWiiaTe+lvJl0eTUYk 4AxcaLCaFDR/MjFEdyNmVeENwyqYcjUzd/krMwQ/XEk4OIjkYf 3P6+MrEnK6HHDq9nD4S/G2alw2ZCjnL Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 937 Lines: 30 On Monday 22 June 2009, Jörn Engel wrote: > Four loops doing the same increment with different data types: long, > u64, we32 (wrong-endian) and we64. Compile with no optimizations. > > Results on my i386 notebook: > long: 453953 us > we32: 880273 us > u64: 504214 us > we64: 2259953 us > loops: 100000000 (couldn't resist) The we64 number is artificially high because the glibc bswap_64 implementation forces the conversion to be done on the stack. Using __builtin_bswap64 make this look more logical, and makes your point even stronger (on core 2, using -m32): long: 236792 us we32: 500827 us u64: 265990 us we64: 757380 us loops: 100000000 Arnd <>< -- 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/