From owner-freebsd-current Tue Aug 31 11: 1:17 1999 Delivered-To: freebsd-current@freebsd.org Received: from apollo.backplane.com (apollo.backplane.com [209.157.86.2]) by hub.freebsd.org (Postfix) with ESMTP id 48F5D153F3 for ; Tue, 31 Aug 1999 11:01:12 -0700 (PDT) (envelope-from dillon@apollo.backplane.com) Received: (from dillon@localhost) by apollo.backplane.com (8.9.3/8.9.1) id KAA25628; Tue, 31 Aug 1999 10:59:35 -0700 (PDT) (envelope-from dillon) Date: Tue, 31 Aug 1999 10:59:35 -0700 (PDT) From: Matthew Dillon Message-Id: <199908311759.KAA25628@apollo.backplane.com> To: Kevin Street Cc: Soren Schmidt , current@FreeBSD.ORG Subject: Re: HEADS UP! ATA driver (atapi DMA).. References: <199908311213.OAA80049@freebsd.dk> <87btbnetgc.fsf@mired.eh.local> Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG :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. :2) I can crash my system (sometimes a panic, sometimes a freeze) with: :dd if=/dev/racd0c of=/dev/null bs=1m count=1 : :I could do bs=1m before the DMA code went in. : :If the system freezes I see: :atapi_error: READ_BIG - timeout error = 00 : :the dd puts out a message about transferring 0 records (This is a different problem, one I can't address. Presumably someone else can). -Matt Matthew Dillon :Kevin Street :street@iname.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message