From owner-freebsd-hackers Tue Jan 26 14:16:15 1999 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id OAA08596 for freebsd-hackers-outgoing; Tue, 26 Jan 1999 14:16:15 -0800 (PST) (envelope-from owner-freebsd-hackers@FreeBSD.ORG) Received: from fledge.watson.org (FLEDGE.RES.CMU.EDU [128.2.93.229]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id OAA08587 for ; Tue, 26 Jan 1999 14:16:14 -0800 (PST) (envelope-from robert@cyrus.watson.org) Received: from fledge.watson.org (robert@fledge.pr.watson.org [192.0.2.3]) by fledge.watson.org (8.8.8/8.8.8) with SMTP id RAA29331; Tue, 26 Jan 1999 17:15:49 -0500 (EST) Date: Tue, 26 Jan 1999 17:15:49 -0500 (EST) From: Robert Watson X-Sender: robert@fledge.watson.org Reply-To: Robert Watson To: "John S. Dyson" cc: rcarter@pinyon.org, hackers@FreeBSD.ORG Subject: Re: Error in vm_fault change In-Reply-To: <199901262114.QAA01098@y.dyson.net> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Tue, 26 Jan 1999, John S. Dyson wrote: > > In Fall, 1997 someone here at CMU stuck a lottery algorithm scheduler into > > FreeBSD, and wrote a paper describing where they had to make changes to > > FreeBSD to allow for more pluggable schedulers. They didn't attempt to > > handle either real-time issues (and hence preemption for in-kernel > > processes) or SMP, but it might be a useful read. I'll see if I can dig > > up a reference. Allowing a pluggable scheduler via a kernel module would > > be pretty cool. > > > I'd love to have a pointer to the paper... John, Here's a URL pointing to the document containing that paper: http://reports-archive.adm.cs.cmu.edu/anon/1998/abstracts/98-103.html The project was done for the graduate level software systems class here, so is with a collection of other papers/projects of varying degrees of quality (some are better than others). The one you're interested in is: Proportional-Share Scheduling: Implementation and Evaluation in a Widely-Deployed Operating System, David Petrou and John Milford, pp. 17-28 In the postscript document, it actually appears to start on page 20. The abstract reads as follows: This paper explores the feasibility of using lottery scheduling, a proportional-share resource management algorithm, to schedule processes under the FreeBSD operating system. Proportional-share scheduling enables flexible control over relative process execution rates and processor load insulation among groups of processes. We show that a straight implementation of lottery scheduling performs worse than the standard FreeBSD scheduler. This initial result prompted us to extend lottery scheduling. Except for one test we run, our resulting system performs within one percent of the FreeBSD scheduler. We describe our design, evaluate our implementation, and relate our experience in deploying our lottery scheduler on production machines. Robert N Watson robert@fledge.watson.org http://www.watson.org/~robert/ PGP key fingerprint: 03 01 DD 8E 15 67 48 73 25 6D 10 FC EC 68 C1 1C Carnegie Mellon University http://www.cmu.edu/ TIS Labs at Network Associates, Inc. http://www.tis.com/ SafePort Network Services http://www.safeport.com/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message