Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752361AbZFDRDd (ORCPT ); Thu, 4 Jun 2009 13:03:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750943AbZFDRDZ (ORCPT ); Thu, 4 Jun 2009 13:03:25 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:37324 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750790AbZFDRDZ (ORCPT ); Thu, 4 Jun 2009 13:03:25 -0400 Date: Thu, 4 Jun 2009 10:03:21 -0700 (PDT) From: Linus Torvalds X-X-Sender: torvalds@localhost.localdomain To: "Michael S. Zick" cc: Duane Griffin , Linux Kernel Mailing List , Harald Welte Subject: Re: Linux 2.6.30-rc8 [also: VIA Support] In-Reply-To: <200906041121.30845.lkml@morethan.org> Message-ID: References: <200906041121.30845.lkml@morethan.org> User-Agent: Alpine 2.01 (LFD 1184 2008-12-16) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1328 Lines: 30 On Thu, 4 Jun 2009, Michael S. Zick wrote: > > The C7-M processor uses "in-order retirement" not "out-of-order" - - > I think the MCR's **should not** be set for "weak ordered writes" - In-order retirement does not really imply anything at all about how write ordering works out. In most CPU parlance, you'd say that you've "retired" a write instruction when it has completed in the write queue - but it would not mean anything in particular for memory ordering. Of course, I don't think the C7 is just in-order retirement, I think it's pretty much in-order everything. Usually you only specify that "retirement" part when there is some out-of-order execution in other parts of the pipeline, but I think the C7 is entirely in-order pipeline, although I suspect the FPU side is likely somewhat separated. But still, with a write buffer (and _no_ sane x86 does not have a write buffer), that doesn't actually mean that the cache and memory accesses are necessarily entirely in-order. That said, how all the internal CPU registers are set is all black magic. 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/