From owner-freebsd-current Tue Aug 31 12:14:41 1999 Delivered-To: freebsd-current@freebsd.org Received: from mail.rdc2.on.home.com (ha1.rdc2.on.home.com [24.9.0.15]) by hub.freebsd.org (Postfix) with ESMTP id 3C1661511A for ; Tue, 31 Aug 1999 12:14:30 -0700 (PDT) (envelope-from street@iname.com) Received: from mired.eh.local ([24.64.136.188]) by mail.rdc2.on.home.com (InterMail v4.01.01.07 201-229-111-110) with ESMTP id <19990831191402.MNRM5161.mail.rdc2.on.home.com@mired.eh.local>; Tue, 31 Aug 1999 12:14:02 -0700 Received: (from kws@localhost) by mired.eh.local (8.9.3/8.9.3) id PAA01761; Tue, 31 Aug 1999 15:14:02 -0400 (EDT) (envelope-from kws) To: Matthew Dillon Cc: Soren Schmidt , current@FreeBSD.ORG Subject: Re: HEADS UP! ATA driver (atapi DMA).. References: <199908311213.OAA80049@freebsd.dk> <87btbnetgc.fsf@mired.eh.local> <199908311759.KAA25628@apollo.backplane.com> From: Kevin Street Date: 31 Aug 1999 15:14:01 -0400 In-Reply-To: Matthew Dillon's message of "Tue, 31 Aug 1999 10:59:35 -0700 (PDT)" Message-ID: <87906repae.fsf@mired.eh.local> Lines: 27 X-Mailer: Gnus v5.6.45/XEmacs 21.1 - "20 Minutes to Nikko" Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Matthew Dillon writes: > :Two things I've noticed: > :1) my cdrom delivers about 2M/s which is the same as before DMA. Is > :the improvement only in cpu usage or should I be seeing a speed > :improvement too? > : > :speed tested with: > :dd if=/dev/racd0c of=/dev/null bs=64k count=320 > :(I get it to spin up with another dd before this test) > > Well 2MB/sec == 14x CDRom drive. Is it a 14x CDRom drive? CDRom > drives are typically limited to how quickly they can get data off > the platter. A faster bus transfer will not improve that. I should have mentioned that ... it's a 32x cdrom. dmesg says it claims to be able to do 5515 KB/sec. I've played around with using dd ... skip=n to reposition which part of the cd I'm reading and I've seen some much better speeds on the outer tracks (I think I now recall that cd's start numbering from the inside tracks, don't they?). So you're probably right that it's just the rotational speed that I was seeing. -- Kevin Street street@iname.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message