From owner-freebsd-arch Tue Jan 28 8:29:44 2003 Delivered-To: freebsd-arch@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id CFD5F37B401 for ; Tue, 28 Jan 2003 08:29:42 -0800 (PST) Received: from fledge.watson.org (fledge.watson.org [204.156.12.50]) by mx1.FreeBSD.org (Postfix) with ESMTP id 3105F43F43 for ; Tue, 28 Jan 2003 08:29:42 -0800 (PST) (envelope-from robert@fledge.watson.org) Received: from fledge.watson.org (fledge.pr.watson.org [192.0.2.3]) by fledge.watson.org (8.12.6/8.12.5) with SMTP id h0SGTFP4094113; Tue, 28 Jan 2003 11:29:16 -0500 (EST) (envelope-from robert@fledge.watson.org) Date: Tue, 28 Jan 2003 11:29:14 -0500 (EST) From: Robert Watson X-Sender: robert@fledge.watson.org To: Julian Elischer Cc: Jeff Roberson , Matthew Dillon , Steve Kargl , Gary Jennejohn , arch@FreeBSD.ORG Subject: Re: New scheduler - Interactivity fixes In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-arch@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On Sat, 25 Jan 2003, Julian Elischer wrote: > The standard proceedure for adding a new "to be standard" feature is: > > Make the new feature an option, leaving the original as default. Make > the old one as a feature as well. Change the default I know there are other follow-ups to this one, but I couldn't find them, so I'll respond to this (apologies to Julian :-). I noticed recently, perhaps in P4, that Juli Mallett had introduced a "platform" config line for configuration files. It made me wonder whether what we shouldn't consider doing is adding a new "scheduler" directive, i.e.,: scheduler 4bsd #scheduler ule Config(8) could be taught to allow at most one scheduler directive. It would allow zero with a warning ("No scheduler defined at compile-time; one must be loaded as a module"). We'd either introduce a new class similar to OPTIONS, or map the argument of scheduler directly to an option, with the possible risk of getting some false positives in the argument validity checking. While it may well be that at some point we flip to using ULE, but since the idea of pluggable schedulers comes up with relative frequency and there is interest in scheduler research, maintaining the ability to easily plug schedulers sounds like the right strategy, so formalizing it to improve the ease-of-use factor would be useful. (For the humor impaired, we could also use "sched" instead of "scheduler" above.) Robert N M Watson FreeBSD Core Team, TrustedBSD Projects robert@fledge.watson.org Network Associates Laboratories To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message