Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1423279AbXBUXfw (ORCPT ); Wed, 21 Feb 2007 18:35:52 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1423278AbXBUXfw (ORCPT ); Wed, 21 Feb 2007 18:35:52 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:50193 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1423279AbXBUXft (ORCPT ); Wed, 21 Feb 2007 18:35:49 -0500 Date: Thu, 22 Feb 2007 00:31:11 +0100 From: Ingo Molnar To: "Michael K. Edwards" Cc: linux-kernel@vger.kernel.org, Linus Torvalds , Arjan van de Ven , Christoph Hellwig , Andrew Morton , Alan Cox , Ulrich Drepper , Zach Brown , Evgeniy Polyakov , "David S. Miller" , Suparna Bhattacharya , Davide Libenzi , Jens Axboe , Thomas Gleixner Subject: Re: [patch 00/13] Syslets, "Threadlets", generic AIO support, v3 Message-ID: <20070221233111.GB5895@elte.hu> References: <20070221211355.GA7302@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.2i X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -5.3 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-5.3 required=5.9 tests=ALL_TRUSTED,BAYES_00 autolearn=no SpamAssassin version=3.0.3 -3.3 ALL_TRUSTED Did not pass through any untrusted hosts -2.0 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1493 Lines: 30 * Michael K. Edwards wrote: > 4) AIO vsyscalls whose semantics resemble those of IEEE 754 floating > point operations, with a clear distinction between a) pipeline state > vs. operands, b) results vs. side effects, and c) coding errors vs. > not-a-number results vs. exceptions that cost you a pipeline flush and > nonlocal branch. threadlets (and syslets) are parallel contexts and they behave so - queuing and execution semantics are then ontop of that, implemented either by glibc, or implemented by the application. There is no 'pipeline' of requests imposed - the structure of pending requests is totally free-form. For example in threadlet-test.c i've in essence implemented a 'set of requests' with the submission site only interested in whether all requests are done or not - but any stricter (or even looser) semantics and ordering can be used too. in terms of AIO, the best queueing model is i think what the kernel uses internally: freely ordered, with barrier support. (That is equivalent to a "queue of sets", where the queue are the barriers, and the sets are the requests within barriers. If there is no barrier pending then there's just one large freely-ordered set of requests.) Ingo - 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/