From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1946168AbXBBXhO (ORCPT ); Fri, 2 Feb 2007 18:37:14 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1946171AbXBBXhO (ORCPT ); Fri, 2 Feb 2007 18:37:14 -0500 Received: from x35.xmailserver.org ([64.71.152.41]:2814 "EHLO x35.xmailserver.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1946169AbXBBXhM (ORCPT ); Fri, 2 Feb 2007 18:37:12 -0500 X-AuthUser: davidel@xmailserver.org Date: Fri, 2 Feb 2007 15:37:09 -0800 (PST) From: Davide Libenzi X-X-Sender: davide@alien.or.mcafeemobile.com To: Ingo Molnar cc: Linus Torvalds , Zach Brown , 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: <20070202222110.GA1212@elte.hu> Message-ID: References: <20070201083611.GC18233@elte.hu> <20070202104900.GA13941@elte.hu> <20070202222110.GA1212@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 Fri, 2 Feb 2007, Ingo Molnar wrote: > in fact an app could also /trigger/ the execution of a syscall in a > different context - to create parallelism artificially - without any > blocking event. So we could do: > > cookie1 = sys_async(sys_read, params); > cookie2 = sys_async(sys_write, params); > > [ ... calculation loop ... ] > > wait_on_async_syscall(cookie1); > wait_on_async_syscall(cookie2); > > or something like that. Without user-space having to create threads > itself, etc. So basically, we'd make kernel threads more useful, and > we'd make threading safer - by only letting syscalls thread. Since I still think that the many-thousands potential async operations coming from network sockets are better handled with a classical event machanism [1], and since smooth integration of new async syscall into the standard POSIX infrastructure is IMO a huge win, I think we need to have a "bridge" to allow async completions being detectable through a pollable (by the mean of select/poll/epoll whatever) device. In that way you can handle async operations with the best mechanism that is fit for them, and gather them in a single async scheduler. [1] Unless you really want to have thousands of kthreads/fibrils lingering on the system. - Davide