From owner-freebsd-hackers Tue Mar 26 7:38:27 2002 Delivered-To: freebsd-hackers@freebsd.org Received: from dan.emsphone.com (dan.emsphone.com [199.67.51.101]) by hub.freebsd.org (Postfix) with ESMTP id 1F0B237B417 for ; Tue, 26 Mar 2002 07:38:23 -0800 (PST) Received: from dan.emsphone.com (smmsp@localhost [127.0.0.1]) by dan.emsphone.com (8.12.2/8.12.2) with ESMTP id g2QFb1xv057406; Tue, 26 Mar 2002 09:38:21 -0600 (CST) (envelope-from dan@dan.emsphone.com) Received: (from dan@localhost) by dan.emsphone.com (8.12.2/8.12.2/Submit) id g2QFZfg5056636; Tue, 26 Mar 2002 09:35:41 -0600 (CST) Date: Tue, 26 Mar 2002 09:35:41 -0600 From: Dan Nelson To: Andrew Cc: Volker Stolz , Ian , hackers@FreeBSD.ORG Subject: Re: idprio Message-ID: <20020326153541.GF17825@dan.emsphone.com> References: <20020326121046.A3952@margaux.informatik.rwth-aachen.de> <20020326232510.A21338-100000@starbug.ugh.net.au> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20020326232510.A21338-100000@starbug.ugh.net.au> User-Agent: Mutt/1.3.28i X-OS: FreeBSD 5.0-CURRENT X-message-flag: Outlook Error Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG In the last episode (Mar 26), Andrew said: > On Tue, 26 Mar 2002, Volker Stolz wrote: > > Under FreeBSD system calls are currently never preempted, therefore > > non- realtime processes can starve realtime processes, or idletime > > processes can starve normal priority processes. > > Even so an idprio process can't be worse than a normal process. Sure it can, if the idprio process has locked a vnode trying to update the contents of a file, and another non-idprio process starts consuming 100% CPU. The idprio process never gets a chance to run again, and if that vnode happened to be an important one (say for /), you may not be able to kill the other process without rebooting. -- Dan Nelson dnelson@allantgroup.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message