From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Wed, 20 May 2009 08:08:02 +0100 (BST) Received: from h5.dl5rb.org.uk ([81.2.74.5]:34423 "EHLO h5.dl5rb.org.uk" rhost-flags-OK-OK-OK-OK) by ftp.linux-mips.org with ESMTP id S20024712AbZETHHy (ORCPT ); Wed, 20 May 2009 08:07:54 +0100 Received: from h5.dl5rb.org.uk (localhost.localdomain [127.0.0.1]) by h5.dl5rb.org.uk (8.14.3/8.14.3) with ESMTP id n4K77LLa017157; Wed, 20 May 2009 08:07:22 +0100 Received: (from ralf@localhost) by h5.dl5rb.org.uk (8.14.3/8.14.3/Submit) id n4K77Jc2017155; Wed, 20 May 2009 08:07:19 +0100 Date: Wed, 20 May 2009 08:07:19 +0100 From: Ralf Baechle To: yanh Cc: Wu Zhangjin , linux-mips@linux-mips.org, Arnaud Patard , loongson-dev@googlegroups.com, zhangfx@lemote.com, Philippe Vachon , Zhang Le , Erwan Lerale Subject: Re: [PATCH 26/30] loongson: flush irq write operation Message-ID: <20090520070719.GA24231@linux-mips.org> References: <1242426527.10164.174.camel@falcon> <20090518163603.GA22779@linux-mips.org> <1242700637.4382.21.camel@localhost.localdomain> <20090519160117.GA19672@linux-mips.org> <1242786494.4382.58.camel@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1242786494.4382.58.camel@localhost.localdomain> User-Agent: Mutt/1.5.18 (2008-05-17) Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 22836 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: ralf@linux-mips.org Precedence: bulk X-list: linux-mips On Wed, May 20, 2009 at 10:28:14AM +0800, yanh wrote: > I have test this patch just now. It works well on yeeloong. Thanks for testing. > I have one question what's the difference between the two patch? Uncached writes can't be re-ordered. By adding a read after the last write my patch forces not only completion of the preceding write but due to this ordering constraint also completion of all preceding writes is enforced. I/O space writes are slow. I mean slower than slugs in space. So my patch is an optimization but that was not the point; I really only meant to verify that we understood what's going on and we seem to. Now let's fix the real issue and make outX() non-posted. Ralf