From owner-freebsd-hackers Tue Nov 12 8:11:29 2002 Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 2F2B037B401; Tue, 12 Nov 2002 08:11:28 -0800 (PST) Received: from mail.eecs.harvard.edu (bowser.eecs.harvard.edu [140.247.60.24]) by mx1.FreeBSD.org (Postfix) with ESMTP id 9A7E043E75; Tue, 12 Nov 2002 08:11:27 -0800 (PST) (envelope-from ellard@eecs.harvard.edu) Received: by mail.eecs.harvard.edu (Postfix, from userid 465) id 509D654C659; Tue, 12 Nov 2002 11:11:21 -0500 (EST) Received: from localhost (localhost [127.0.0.1]) by mail.eecs.harvard.edu (Postfix) with ESMTP id 4947254C634; Tue, 12 Nov 2002 11:11:21 -0500 (EST) Date: Tue, 12 Nov 2002 11:11:21 -0500 (EST) From: Dan Ellard To: freebsd-fs@FreeBSD.ORG, Subject: how to control tagged queueing? Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII 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 I'm experimenting with the effects of SCSI tagged queueing on file system performance. Is there any kind of global toggle somewhere in the kernel to turn tagged queueing on and off, and/or knob to limit the number of outstanding tags? Tagged queue management all seems to be done at the device level, and I haven't found hooks for controlling it at a higher level (but I thought I'd ask before running off to write something). I'm running 4.6.2p4, in case things have changed. (If there's a nicer interface in 4.7, I'll install it immediately!) Thanks, -Dan To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message