Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932463AbXBWRnU (ORCPT ); Fri, 23 Feb 2007 12:43:20 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932472AbXBWRnU (ORCPT ); Fri, 23 Feb 2007 12:43:20 -0500 Received: from x35.xmailserver.org ([64.71.152.41]:1192 "EHLO x35.xmailserver.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932463AbXBWRnT (ORCPT ); Fri, 23 Feb 2007 12:43:19 -0500 X-AuthUser: davidel@xmailserver.org Date: Fri, 23 Feb 2007 09:43:14 -0800 (PST) From: Davide Libenzi X-X-Sender: davide@alien.or.mcafeemobile.com To: Evgeniy Polyakov cc: Ingo Molnar , Ulrich Drepper , Linux Kernel Mailing List , Linus Torvalds , Arjan van de Ven , Christoph Hellwig , Andrew Morton , Alan Cox , Zach Brown , "David S. Miller" , Suparna Bhattacharya , Jens Axboe , Thomas Gleixner Subject: Re: [patch 00/13] Syslets, "Threadlets", generic AIO support, v3 In-Reply-To: <20070223121521.GA5392@2ka.mipt.ru> Message-ID: References: <20070221211355.GA7302@elte.hu> <20070221233111.GB5895@elte.hu> <45DCD9E5.2010106@redhat.com> <20070222074044.GA4158@elte.hu> <20070222113148.GA3781@2ka.mipt.ru> <20070222125931.GB25788@elte.hu> <20070222133201.GB5208@2ka.mipt.ru> <20070223121521.GA5392@2ka.mipt.ru> 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 Content-Length: 1889 Lines: 47 On Fri, 23 Feb 2007, Evgeniy Polyakov wrote: > On Thu, Feb 22, 2007 at 11:46:48AM -0800, Davide Libenzi (davidel@xmailserver.org) wrote: > > > > A dynamic pool will smooth thread creation/freeing up by a lot. > > And, in my box a *pthread* create/free takes ~10us, at 1000/s is 10ms, 1%. > > Bad, but not so aweful ;) > > Look, I'm *definitely* not trying to advocate the use of async syscalls for > > network here, just pointing out that when we're talking about threads, > > Linux does a pretty good job. > > If we are going to create 1000 threads each second, then it is better to > preallocate them and queue a work to that pool - like syslets did with > syscalls, but not ulitimately create a new thread just because it is not > that slow. We do create a pool indeed, as I said in the opening of my asnwer. The numbers I posted was just to show that thread creation/destroy is pretty fast, but that does not justify it as a design choice. > All such micro-thread designs are especially good in the case when > 1. switching is _rare_ (very) > 2. programmer does not want to create complex model to achieve maximum > performance > > Disk (cached) IO definitely hits first entry and second one is there for > advertisements and fast deployment, but overall usage of the > asynchronous IO model is not limited to the above scenario, so > micro-threads definitely hit own niche, but they can not cover all usage > cases. You know, I read this a few times, but I still don't get what your point is here ;) Are you talking about micro-thread design in the kernel as for kthreads usage for AIO, or about userspace? - Davide - 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/