From owner-freebsd-alpha Thu Sep 5 12: 6:45 2002 Delivered-To: freebsd-alpha@freebsd.org Received: from mx1.FreeBSD.org (mx1.FreeBSD.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id D995D37B400 for ; Thu, 5 Sep 2002 12:06:42 -0700 (PDT) Received: from mail.speakeasy.net (mail15.speakeasy.net [216.254.0.215]) by mx1.FreeBSD.org (Postfix) with ESMTP id 79CAA43E65 for ; Thu, 5 Sep 2002 12:06:42 -0700 (PDT) (envelope-from jhb@FreeBSD.org) Received: (qmail 19780 invoked from network); 5 Sep 2002 19:06:41 -0000 Received: from unknown (HELO server.baldwin.cx) ([216.27.160.63]) (envelope-sender ) by mail15.speakeasy.net (qmail-ldap-1.03) with DES-CBC3-SHA encrypted SMTP for ; 5 Sep 2002 19:06:41 -0000 Received: from laptop.baldwin.cx (gw1.twc.weather.com [216.133.140.1]) by server.baldwin.cx (8.12.5/8.12.5) with ESMTP id g85J6eBv012091; Thu, 5 Sep 2002 15:06:40 -0400 (EDT) (envelope-from jhb@FreeBSD.org) Message-ID: X-Mailer: XFMail 1.5.2 on FreeBSD X-Priority: 3 (Normal) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8bit MIME-Version: 1.0 In-Reply-To: <15735.38318.66517.366474@grasshopper.cs.duke.edu> Date: Thu, 05 Sep 2002 15:06:40 -0400 (EDT) From: John Baldwin To: Andrew Gallatin Subject: RE: ithread preemption Cc: freebsd-alpha@freebsd.org Sender: owner-freebsd-alpha@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org On 05-Sep-2002 Andrew Gallatin wrote: > > I've forgotten -- What are the symptoms of ithread preemption causing > troubles on alpha? Hangs on SMP under load. > I have one (probably dumb) idea: Is the ithread preemption code > guaranteed to switch back to the preempted thread when the ithread > completes or blocks? And continue through to the end of the interrupt > dispatch code, returning back to the palcode? It is not guaranteed to do that. > Eg, I'm wondering if it could it have anything to do with continuing > to run at IPL_IO when we shouldn't be (like running a normal > process at that priority that the scheduler happened to run by mistake). Nope, IPL changes when you switch threads. -- John Baldwin <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-alpha" in the body of the message