From owner-freebsd-current Mon Dec 3 22:33:47 2001 Delivered-To: freebsd-current@freebsd.org Received: from apollo.backplane.com (apollo.backplane.com [216.240.41.2]) by hub.freebsd.org (Postfix) with ESMTP id C425B37B417; Mon, 3 Dec 2001 22:33:45 -0800 (PST) Received: (from dillon@localhost) by apollo.backplane.com (8.11.6/8.9.1) id fB46XgI16876; Mon, 3 Dec 2001 22:33:42 -0800 (PST) (envelope-from dillon) Date: Mon, 3 Dec 2001 22:33:42 -0800 (PST) From: Matthew Dillon Message-Id: <200112040633.fB46XgI16876@apollo.backplane.com> To: Søren Schmidt Cc: nuzrin@goose.net.my, Miklos Niedermayer , Greg Lehey , current@FreeBSD.ORG Subject: Re: HEADSUP ATA support for newer SiS chipsets added References: <200112040619.fB46Jd786535@freebsd.dk> Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG :> :sits on irq 14 & 15 making them the lowest priority devices in the system, :> :and that could cause the interrupt latency I'm seeing which then again :> :causes the bad transfer rates on transfers that need to transfer more :> :that one transaction full of data (ie max 128k). :> : :> :-Søren :> :> The larger transfers are probably choking the IDE drive's pipelining :> capabilities. That's my guess, anyway. I avoid IDE like the plague. : :No, not true, if the same drive is put on a PCI based ATA controller :you get the expected transfer speed upto the drives cache size. : :-Søren Ahhh. Hmm. That is very odd then. Even at irq 14/15 the interrupt priority should not make a difference, at least not in a simple test when the machine isn't doing anything else. -Matt Matthew Dillon To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message