Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261334AbTIJKV0 (ORCPT ); Wed, 10 Sep 2003 06:21:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261427AbTIJKV0 (ORCPT ); Wed, 10 Sep 2003 06:21:26 -0400 Received: from mid-1.inet.it ([213.92.5.18]:56503 "EHLO mid-1.inet.it") by vger.kernel.org with ESMTP id S261334AbTIJKVZ (ORCPT ); Wed, 10 Sep 2003 06:21:25 -0400 Message-ID: <024601c37785$e3e07680$5aaf7450@wssupremo> Reply-To: "Luca Veraldi" From: "Luca Veraldi" To: "Arjan van de Ven" Cc: "linux-kernel" References: <00f201c376f8$231d5e00$beae7450@wssupremo> <20030909175821.GL16080@Synopsys.COM> <001d01c37703$8edc10e0$36af7450@wssupremo> <20030910064508.GA25795@Synopsys.COM> <015601c3777c$8c63b2e0$5aaf7450@wssupremo> <1063185795.5021.4.camel@laptop.fenrus.com> <01c601c3777f$97c92680$5aaf7450@wssupremo> <20030910114414.B14352@devserv.devel.redhat.com> <01f801c37783$9ead8960$5aaf7450@wssupremo> <20030910121453.B9878@devserv.devel.redhat.com> Subject: Re: Efficient IPC mechanism on Linux Date: Wed, 10 Sep 2003 12:25:41 +0200 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1106 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 945 Lines: 26 > I'm saying it can. I don't want to go too deep into an arguement about > microarchitectural details, but my point was that a memory copy of a page > is NOT super expensive relative to several other effects that have to do > with pagetable manipulations. Sorry, but I cannot believe it. Reading a page tagle entry and storing in into a struct capability is not comparable at all with the "for" needed to move bytes all around memory. > but the pipe code cannot know this so it has to do a cross cpu invalidate. Sorry for you. Don't knowning does not justify it. It's inefficient. > and... which is also releasing it before the copy Oh, yes. After wasting thousands of cycles, sure. Bye, Luca. - 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/