From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933405AbXBET02 (ORCPT ); Mon, 5 Feb 2007 14:26:28 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S933406AbXBET01 (ORCPT ); Mon, 5 Feb 2007 14:26:27 -0500 Received: from x35.xmailserver.org ([64.71.152.41]:4070 "EHLO x35.xmailserver.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933405AbXBET01 (ORCPT ); Mon, 5 Feb 2007 14:26:27 -0500 X-AuthUser: davidel@xmailserver.org Date: Mon, 5 Feb 2007 11:26:23 -0800 (PST) From: Davide Libenzi X-X-Sender: davide@alien.or.mcafeemobile.com To: Zach Brown cc: Ingo Molnar , Linus Torvalds , Linux Kernel Mailing List , linux-aio@kvack.org, Suparna Bhattacharya , Benjamin LaHaise Subject: Re: [PATCH 2 of 4] Introduce i386 fibril scheduling In-Reply-To: Message-ID: References: <20070201083611.GC18233@elte.hu> <20070202104900.GA13941@elte.hu> <20070202222110.GA1212@elte.hu> <20070202235531.GA18904@elte.hu> <20070203082308.GA6748@elte.hu> X-GPG-FINGRPRINT: CFAE 5BEE FD36 F65E E640 56FE 0974 BF23 270F 474E X-GPG-PUBLIC_KEY: http://www.xmailserver.org/davidel.asc 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 On Mon, 5 Feb 2007, Zach Brown wrote: > > The normal and most optimal workflow should be a user-space ring-buffer > > of these constant-size struct async_syscall entries: > > > > struct async_syscall ringbuffer[1024]; > > > > LIST_HEAD(submitted); > > LIST_HEAD(pending); > > LIST_HEAD(completed); > > I strongly disagree here, and I'm hoping you're not as keen on this now -- > your reply to Matt gives me hope. > > As mentioned, that they complete out-of-order leads, at least, to having > separate submission and completion rings. I'm not sure a submission ring > makes any sense given the goal of processing the calls in submission and only > creating threads if it blocks. A simple copy of an array of these input > structs sounds fine to me. The "result" of one async operation is basically a cookie and a result code. Eight or sixteen bytes at most. IMO, before going wacko designing complex shared userspace-kernel result buffers, I think it'd be better measuring the worth-value of the thing ;) - Davide