From owner-freebsd-arch@FreeBSD.ORG Thu Aug 11 14:41:37 2005 Return-Path: X-Original-To: freebsd-arch@freebsd.org 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 309E616A420; Thu, 11 Aug 2005 14:41:37 +0000 (GMT) (envelope-from jhb@FreeBSD.org) Received: from mv.twc.weather.com (mv.twc.weather.com [65.212.71.225]) by mx1.FreeBSD.org (Postfix) with ESMTP id 3045643D49; Thu, 11 Aug 2005 14:41:36 +0000 (GMT) (envelope-from jhb@FreeBSD.org) Received: from [10.50.40.201] (Not Verified[65.202.103.25]) by mv.twc.weather.com with NetIQ MailMarshal (v6, 0, 3, 8) id ; Thu, 11 Aug 2005 10:56:26 -0400 From: John Baldwin To: freebsd-arch@freebsd.org Date: Thu, 11 Aug 2005 09:13:10 -0400 User-Agent: KMail/1.8 References: <42F9ECF2.8080809@freebsd.org> <20050810.162006.48492066.imp@bsdimp.com> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200508110913.11867.jhb@FreeBSD.org> Cc: gnn@freebsd.org Subject: Re: Special schedulers, one CPU only kernel, one only userland X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 11 Aug 2005 14:41:37 -0000 On Wednesday 10 August 2005 10:10 pm, gnn@freebsd.org wrote: > But, the question, which is interesting to me for other reasons > (namely putting in various real-time schedulers) was not answered. Do > we currently have the requisite primitives to implement different > schedulers or is there still a lot of jiggery/pokery required? Yes, there is some room for different schedulers, but the idea of using a master/slave SMP system is not ust a different scheduler, but an entirely different SMP architecture. That said, if you added one more sched_foo call for synchronous kernel entry in trap() and syscall(), you probably could provide a master/slave setup via a custom scheduler. It would be more optimal to also tweak the low-level routing of interrupts to CPUs on architectures that support it as well, though that would not be required. -- John Baldwin <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve" = http://www.FreeBSD.org