Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932667AbWCIAyg (ORCPT ); Wed, 8 Mar 2006 19:54:36 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932669AbWCIAyg (ORCPT ); Wed, 8 Mar 2006 19:54:36 -0500 Received: from smtp.osdl.org ([65.172.181.4]:42442 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S932665AbWCIAyf (ORCPT ); Wed, 8 Mar 2006 19:54:35 -0500 Date: Wed, 8 Mar 2006 16:54:08 -0800 (PST) From: Linus Torvalds To: Paul Mackerras cc: David Howells , Alan Cox , akpm@osdl.org, mingo@redhat.com, linux-arch@vger.kernel.org, linuxppc64-dev@ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] Document Linux's memory barriers [try #2] In-Reply-To: <17423.30789.214209.462657@cargo.ozlabs.ibm.com> Message-ID: References: <20060308184500.GA17716@devserv.devel.redhat.com> <20060308173605.GB13063@devserv.devel.redhat.com> <20060308145506.GA5095@devserv.devel.redhat.com> <31492.1141753245@warthog.cambridge.redhat.com> <29826.1141828678@warthog.cambridge.redhat.com> <9834.1141837491@warthog.cambridge.redhat.com> <11922.1141842907@warthog.cambridge.redhat.com> <14275.1141844922@warthog.cambridge.redhat.com> <19984.1141846302@warthog.cambridge.redhat.com> <17423.30789.214209.462657@cargo.ozlabs.ibm.com> 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: 739 Lines: 23 On Thu, 9 Mar 2006, Paul Mackerras wrote: > > If you ask me, the need for mmiowb on some platforms merely shows that > those platforms' implementations of spinlocks and read*/write* are > buggy... You could also state that same as "If you ask me, the need for mmiowb on some platforms merely shows that those platforms perform like a bat out of hell, and I think they should be slower" because the fact is, x86 memory barrier rules are just about optimal for performance. 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/