From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 19 Sep 2001 03:11:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 19 Sep 2001 03:11:39 -0400 Received: from c007-h015.c007.snv.cp.net ([209.228.33.222]:12282 "HELO c007.snv.cp.net") by vger.kernel.org with SMTP id ; Wed, 19 Sep 2001 03:11:25 -0400 X-Sent: 19 Sep 2001 07:11:43 GMT Message-ID: <3BA84367.239FA0B4@distributopia.com> Date: Wed, 19 Sep 2001 02:04:07 -0500 From: "Christopher K. St. John" X-Mailer: Mozilla 4.61 [en] (X11; I; Linux 2.0.36 i686) X-Accept-Language: en MIME-Version: 1.0 To: linux-kernel@vger.kernel.org CC: Dan Kegel , davidel@xmailserver.org Subject: Re: [PATCH] /dev/epoll update ... In-Reply-To: <3BA80108.C830D602@kegel.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Dan Kegel wrote: > > I'm getting ready to stress-test /dev/epoll finally. > In porting my Poller_devpoll.{cc,h} to support /dev/epoll, I noticed > the following issues: > Another issue to throw into the mix: The Banga, Mogul and Druschel[1] paper (which I understand was the inspiration for the Solaris /dev/poll which was the inspiration for /dev/epoll?) talks about having the poll return the current state of new descriptors. As far as I can tell, /dev/epoll only gives you events on state changes. So, for example, if you accept() a new socket and add it to the interest list, you (probably) won't get a POLLIN. That's not fatal, but it's awkward. The BMD paper suggests making the behavior optional, but I didn't see anything about it in the Solaris /dev/poll manpage (and I don't have a copy of Solaris to try it out on). My vote would be to always report the initial state, but that would make the driver a little more complicated. What are the preferred semantics? [1] http://citeseer.nj.nec.com/banga99scalable.html -- Christopher St. John cks@distributopia.com DistribuTopia http://www.distributopia.com