From owner-freebsd-arch Wed Jul 17 7:12:37 2002 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 52D1937B400 for ; Wed, 17 Jul 2002 07:12:34 -0700 (PDT) Received: from fledge.watson.org (fledge.watson.org [204.156.12.50]) by mx1.FreeBSD.org (Postfix) with ESMTP id 9BE5643E31 for ; Wed, 17 Jul 2002 07:12:33 -0700 (PDT) (envelope-from robert@fledge.watson.org) Received: from fledge.watson.org (fledge.pr.watson.org [192.0.2.3]) by fledge.watson.org (8.12.4/8.12.4) with SMTP id g6HECROo098312; Wed, 17 Jul 2002 10:12:27 -0400 (EDT) (envelope-from robert@fledge.watson.org) Date: Wed, 17 Jul 2002 10:12:26 -0400 (EDT) From: Robert Watson To: Luigi Rizzo Cc: arch@freebsd.org Subject: Re: proposed changes to kern_switch.c and kern_synch.c In-Reply-To: <20020716235216.B6785@iguana.icir.org> 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 I'm very excited about the idea of a more flexible scheduler interface, as having that tends to encourage scheduler research. The main cautions I have are: (1) In introducing flexibility, be careful to avoid unnecessary costs. In particular, the notion of changing the scheduler at run-time is cool, but not if it involves introducing scary new locks. Being able to support introducing flexible new scheduling algorithms at boot time is very appealing, though. (2) Currently the MD code speaks a few specific MI-defined data structures in the scheduling code. In a move towards a more flexible mechanism for specifying scheduling behavior, hammering down the details of what exactly can and cannot be modified at the C level, and what the assembly code is and is not permitted to assume, is probably a useful piece of this work. 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