Date: Sat, 19 May 2001 18:17:37 +0100 From: Brian Somers <brian@Awfulhak.org> To: S ren Schmidt <sos@freebsd.dk> Cc: achilov@granch.ru, valgog@biofrontera.de, freebsd-bugs@FreeBSD.ORG, brian@Awfulhak.org Subject: Re: ATA driver on 4.3 is too slow Message-ID: <200105191717.f4JHHbb31761@hak.lan.Awfulhak.org> In-Reply-To: Message from S ren Schmidt <sos@freebsd.dk> of "Sat, 19 May 2001 17:02:20 %2B0200." <200105191503.f4JF35V49854@freebsd.dk>
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> It seems Rashid N. Achilov wrote:
> > On Thursday 17 May 2001 18:33, S?ren Schmidt wrote:
> > > It seems valgog@biofrontera.de wrote:
> > >
> > > Most of the impact is due to FreeBSD now shipping with Write Caching
> > > off as default (see man ata for details), that will hurt even if
> > > you run with softupdates. If you dont care about possible dataloss
> > > at power failures you can enable WC and get your performance back...
> >
> > sysctl -w hw.ata.wc=1
> > sysctl: oid 'hw.ata.wc' is read only
>
> Does that mean it still performs badly ? you give no info here...
>
> If so, its hardly the ATA driver thats the problem, you could try
> that by doing a 'dd if=/dev/ad0 of=/dev/null bs=1m count=1000'
> and see if the transfer rate is what the drive can deliver. If
> so you have to look somewhere other than the ATA subsystem.
I think he's saying that he can't change the sysctl to 1.
I can confirm that I get the same poor performance. I can give you
an account on the box if you're interested. It's running -current:
$ pwd
/spare1
$ df .
Filesystem 1K-blocks Used Avail Capacity Mounted on
/dev/ad1s2f 33059676 1 30414901 0% /spare1
$ dmesg | fgrep ad1:
ad1: 73308MB <IBM-DTLA-307075> [148945/16/63] at ata1-master UDMA100
$ mount | fgrep $PWD
/dev/ad1s2f on /spare1 (ufs, local, soft-updates)
$ dd if=/dev/zero of=data bs=1024000 count=500
500+0 records in
500+0 records out
512000000 bytes transferred in 63.359681 secs (8080849 bytes/sec)
$ dd if=data of=/dev/null bs=1024000
500+0 records in
500+0 records out
512000000 bytes transferred in 17.751130 secs (28843234 bytes/sec)
$ sysctl -a | fgrep hw.ata
hw.ata.ata_dma: 1
hw.ata.wc: 0
hw.ata.tags: 0
hw.ata.atapi_dma: 0
$ sudo sysctl -w hw.ata.wc=1
sysctl: oid 'hw.ata.wc' is read only
$ sysctl -a | fgrep hw.ata
hw.ata.ata_dma: 1
hw.ata.wc: 0
hw.ata.tags: 0
hw.ata.atapi_dma: 0
$ dd if=/dev/zero of=data bs=1024000 count=500
500+0 records in
500+0 records out
512000000 bytes transferred in 63.502042 secs (8062733 bytes/sec)
$ dd if=data of=/dev/null bs=1024000
500+0 records in
500+0 records out
512000000 bytes transferred in 18.935320 secs (27039416 bytes/sec)
> -Søren
--
Brian <brian@Awfulhak.org> <brian@[uk.]FreeBSD.org>
<http://www.Awfulhak.org>; <brian@[uk.]OpenBSD.org>
Don't _EVER_ lose your sense of humour !
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