From owner-freebsd-arch Wed Jan 29 10: 4:19 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 65EB537B401; Wed, 29 Jan 2003 10:04:18 -0800 (PST) Received: from HAL9000.homeunix.com (12-233-57-224.client.attbi.com [12.233.57.224]) by mx1.FreeBSD.org (Postfix) with ESMTP id A73A043E4A; Wed, 29 Jan 2003 10:04:17 -0800 (PST) (envelope-from dschultz@uclink.Berkeley.EDU) Received: from HAL9000.homeunix.com (localhost [127.0.0.1]) by HAL9000.homeunix.com (8.12.6/8.12.5) with ESMTP id h0TI45Nt004953; Wed, 29 Jan 2003 10:04:05 -0800 (PST) (envelope-from dschultz@uclink.Berkeley.EDU) Received: (from das@localhost) by HAL9000.homeunix.com (8.12.6/8.12.5/Submit) id h0TI45Me004952; Wed, 29 Jan 2003 10:04:05 -0800 (PST) (envelope-from dschultz@uclink.Berkeley.EDU) Date: Wed, 29 Jan 2003 10:04:05 -0800 From: David Schultz To: Peter Jeremy Cc: Robert Watson , Jeff Roberson , arch@FreeBSD.ORG Subject: Re: New scheduler - Interactivity fixes Message-ID: <20030129180405.GA3139@HAL9000.homeunix.com> Mail-Followup-To: Peter Jeremy , Robert Watson , Jeff Roberson , arch@FreeBSD.ORG References: <20030129094943.GA27833@cirb503493.alcatel.com.au> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20030129094943.GA27833@cirb503493.alcatel.com.au> 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 Thus spake Peter Jeremy : > I'd prefer to allow multiple schedulers to be compiled in (or KLD'd), > with a sysctl to select which one (preferably alterable at runtime). > This reduces(?) the problem to: > - ensure that at least one scheduler is present before trying to use it > - picking a default scheduler when multiple schedulers are present. Some researchers at Microsoft implmeneted dynamically loadable schedulers for Windows NT a few years ago. There idea was to allow applications to load different algorithms for different parts of the system. I think they subsequently developed it to the point where you could have a hierarchy of schedulers, all at the same time. While some of their ideas have the potential to become incredibly complicated on the long and winding path from research prototype to the real world, it may be helpful to look at their design. (Also note that KSE does allow applications to have some control over scheduling policies among their threads and KSEs, so we probably ought to leverage that...AFTER we have a working KSE implementation.) I can't find the Microsoft Research paper that I remember, but I did find an older, less detailed paper on the same topic: http://citeseer.nj.nec.com/candea98vassal.html To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message