From owner-freebsd-stable Mon Mar 1 17:23: 4 1999 Delivered-To: freebsd-stable@freebsd.org Received: from pop.uniserve.com (pop.uniserve.com [204.244.156.3]) by hub.freebsd.org (Postfix) with SMTP id E70B7151AF for ; Mon, 1 Mar 1999 17:23:01 -0800 (PST) (envelope-from tom@uniserve.com) Received: from shell.uniserve.ca [204.244.186.218] by pop.uniserve.com with smtp (Exim 1.82 #4) id 10HdtN-0001zM-00; Mon, 1 Mar 1999 17:22:37 -0800 Date: Mon, 1 Mar 1999 17:22:34 -0800 (PST) From: Tom X-Sender: tom@shell.uniserve.ca To: Andrew McNaughton Cc: freebsd-stable@FreeBSD.ORG Subject: Re: rc5des slows tape thruput In-Reply-To: <199903020010.NAA09186@aniwa.sky> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-stable@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Tue, 2 Mar 1999, Andrew McNaughton wrote: > > Maybe, maybe not. There are device driver issues with scheduling and > > CPU utilization, and with block sizes, and buffering capacity of the > > driver and device. Also an IO bound process will yield to the scheduler a > > lot, and since rc5des is probably never blocked, and it will always take > > slice. If you tape requires another block at that moment, it is just > > going to have to wait. > > So, if rc5des is idprio'ed and the tape process blocks on IO, the > rc5des process doesn't run? Or does the tape process just get control > back quicker when the IO block goes away? I was talking about niced processes. The realtime scheduling used by idprio/rtprio is completely different. > Do you know where I could find detailed docs on this? The man pages > fall short. I'm not sure. > Andrew Tom Systems Support Uniserve To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message