Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 30 Oct 2002 14:32:03 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 30 Oct 2002 14:32:03 -0500 Received: from mailout08.sul.t-online.com ([194.25.134.20]:41898 "EHLO mailout08.sul.t-online.com") by vger.kernel.org with ESMTP id ; Wed, 30 Oct 2002 14:32:02 -0500 Date: Wed, 30 Oct 2002 20:38:10 +0100 From: Martin Waitz To: Davide Libenzi Cc: Linux Kernel Mailing List Subject: Re: and nicer too - Re: [PATCH] epoll more scalable than poll Message-ID: <20021030193810.GD2300@admingilde.org> Mail-Followup-To: Davide Libenzi , Linux Kernel Mailing List References: <20021029225419.GA1463@admingilde.org> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="6WlEvdN9Dv0WHSBl" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2706 Lines: 74 --6WlEvdN9Dv0WHSBl Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable hi :) > > what is the motivation to make it edge based? On Tue, Oct 29, 2002 at 06:24:27PM -0800, Davide Libenzi wrote: > You have two ways to know if "something" changed. You call everyone each > time and you ask him if his changed, or you call everyone one time by > saying "call me when you're changed". well, you don't say 'call me when you're changed' but 'i'm interested in your status, please be prepared to report if you have changed' when calling epoll_ctl. > It's behind the "call me when you're changed" phrase that lays the > concept of edge triggered APIs. in most situations, you are not really interested in 'has it changed?' but in 'what has it changed to?'. this is the difference between edge- or level-triggered notification. e.g. the application wants to know 'from which fds can i read without blocking' and not which fds happend to change their block-state (perhaps there is still data available after the last read, in which case the application would like to be notified about this situation) > So, pretty evidently, the answer to your question is : efficency. but the api should be useful, too... is it possible that www.xmailserver.org is down atm? i couldn't get as much docu about epoll as i wanted to, so please correct me if my above view about epoll is incorrect and yes, i haven't looked at any code yet, i just like the kevent docu better then the epoll docu... ;) and yes, i would like to port kevent to linux, but i don't have any time to do this in the next months... :( --=20 CU, / Friedrich-Alexander University Erlangen, Germany Martin Waitz // [Tali on IRCnet] [tali.home.pages.de] _________ ______________/// - - - - - - - - - - - - - - - - - - - - /// dies ist eine manuell generierte mail, sie beinhaltet // tippfehler und ist auch ohne grossbuchstaben gueltig. / - Wer bereit ist, grundlegende Freiheiten aufzugeben, um sich=20 kurzfristige Sicherheit zu verschaffen, der hat weder Freiheit=20 noch Sicherheit verdient. Benjamin Franklin (1706 - 1790) --6WlEvdN9Dv0WHSBl Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.1 (GNU/Linux) iD8DBQE9wDUij/Eaxd/oD7IRAnKUAJ9RBerF9O+Xf7saRElAHVee6CPrzwCfRtUf Dce/hHmVSVHLZnbC3tcrVZo= =lgva -----END PGP SIGNATURE----- --6WlEvdN9Dv0WHSBl-- - 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/