Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261478AbUJ2Tnk (ORCPT ); Fri, 29 Oct 2004 15:43:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263478AbUJ2TkP (ORCPT ); Fri, 29 Oct 2004 15:40:15 -0400 Received: from fw.osdl.org ([65.172.181.6]:39120 "EHLO mail.osdl.org") by vger.kernel.org with ESMTP id S261633AbUJ2TMO (ORCPT ); Fri, 29 Oct 2004 15:12:14 -0400 Date: Fri, 29 Oct 2004 12:12:07 -0700 (PDT) From: Linus Torvalds To: linux-os@analogic.com cc: Andreas Steinmetz , Kernel Mailing List , Richard Henderson , Andi Kleen , Andrew Morton , Jan Hubicka Subject: Re: Semaphore assembly-code bug In-Reply-To: Message-ID: References: <417550FB.8020404@drdos.com> <1098218286.8675.82.camel@mentorng.gurulabs.com> <41757478.4090402@drdos.com> <20041020034524.GD10638@michonline.com> <1098245904.23628.84.camel@krustophenia.net> <1098247307.23628.91.camel@krustophenia.net> <41826A7E.6020801@domdv.de> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 866 Lines: 35 On Fri, 29 Oct 2004, linux-os wrote: > > Linus, there is no way in hell that you are going to move > a value from memory into a register (pop ecx) faster than > you are going to do anything to the stack-pointer or > any other register. Sorry, but you're wrong. Learn about modern CPU's some day, and realize that cached accesses are fast, and pipeline stalls are relatively much more expensive. Now, if it was uncached, you'd have a point. Also think about why call xxx jmp yy is often much faster than push $yy jmp xxx and other small interesting facts about how CPU's actually work these days. Linus - 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/