From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 24 Sep 2001 17:30:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 24 Sep 2001 17:30:17 -0400 Received: from host154.207-175-42.redhat.com ([207.175.42.154]:39883 "EHLO lacrosse.corp.redhat.com") by vger.kernel.org with ESMTP id ; Mon, 24 Sep 2001 17:30:04 -0400 Date: Mon, 24 Sep 2001 17:30:29 -0400 From: Benjamin LaHaise To: Simon Kirby Cc: Matti Aarnio , "Eric W. Biederman" , linux-kernel@vger.kernel.org Subject: Re: O_NONBLOCK on files Message-ID: <20010924173029.J17683@redhat.com> In-Reply-To: <20010918234648.A21010@netnation.com> <20010919002439.A21138@netnation.com> <20010924234717.V11046@mea-ext.zmailer.org> <20010924140534.E2335@netnation.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <20010924140534.E2335@netnation.com>; from sim@netnation.com on Mon, Sep 24, 2001 at 02:05:34PM -0700 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 24, 2001 at 02:05:34PM -0700, Simon Kirby wrote: > Yes, but this sucks. My whole intent was an interface design that would > never need to context switch. I'm not sure if this is even possible, but > if so it would be very nice from a userspace perspective. Actually, this was one of the design concerns that I had in coming up with the async io interfaces. The interface was designed to make use of the upcoming syscalls-in-userspace stubs that x86-64 implemented and will be passed on to x86 in 2.5. All completion events are passed through a ring buffer with minimal locking on the kernel side which only needs thread locking in userspace. This way the whole userspace to kernel transition can be avoided by the server under sufficiently high load. -ben