7 Sep
2004
7 Sep
'04
4:19 p.m.
Matt Barber wrote:
So,
At home I had been getting some odd latency with my cd/dvd drive (using
jack and alsaplayer, the sound would cut out for a split second, but
with no xruns, so I'm thinking it was the drive or the ide channel, and
not jack-related). I have an nforce2-based motherboard, with a seagate
SATA drive (nforce2 puts SATA on the primary master ide channel),
another seagate ide drive, and a pioneer cd/dvd drive. I keep all my
soundfiles on the SATA drive (since it's supposed to be faster), and the
linux system on the ide drive. My previous setup gave the SATA drive
the entire primary channel, put the system drive as secondary master and
dvd as secondary slave. I decided to try putting the system drive on
the primary channel as slave, and giving the entire secondary channel to
the dvd drive as master (this is a setup I have used successfully with
other motherboards). So - sound drive is hda, system drive is hdb, and
dvd is hdc. Here's the problem-- where I had been getting about
33-35MB/sec on both drives with the previous setup with hdparm -t, when
I set it up like this, they both go down to about 6.5MB/sec. This is
because dma has been disabled - when I enable it on hdb (hdparm -d1
/dev/hdb) the benchmark runs back up to around 35. On hda, I can enable
dma with no errors:
# hdparm -d1 /dev/hda
/dev/hda:
setting using_dma to 1 (on)
using_dma = 1 (on)
but when I run the benchmark it's still around 6.5MB/sec, and then I
notice that dma has again been disabled on BOTH hda and hdb. Anybody
know what the hell is going on here? My guess is that the SATA-ide
driver won't allow dma (or the default udma mode is wrong or something),
and when the SATA drive gets its own ide channel, there's no problem -
it's only when it's combined with other drives that there's a problem
(it does the same when the cdrom is placed on primary/slave).
I'm getting fewer cutouts from the dvd drive (secondary master by
itself) when I play a cd, but I'm still getting a few now and then - is
there a way to optimize something here so I don't get them?
Thanks,
Matt
Matt,
Not sure I can help, but I end up with a few questions from reading
this. Maybe your answers will lead someone else to give you a good
pointer. Mostly I'm confused about your hda/hdb comments with respect to
SATA drives which are normally on a cable by themselves. In my
experience hda/hdb are the EIDE drive designations. With two controllers
you then get hda-hdd for EIDE and hde for SATA.
If you are really using EIDE drives then switching the order of the
drives can be a problem *if* the drives were not configured for
auto-detect *and* you forgot to chenge the jumpers. I don't know if this
would cause the problem that you are seeing though.
I think I'm just misunderstanding your setup. Maybe the NForce-2
allows other options? Not sure.
I built a SATA machine for my dad about a year ago. (nforce?
nforce-2? Don't remember) On his machine the SATA drive is hde. It has
EIDE channels, and I used them for the CDRW drive, but it was a bit
tricky getting it all configured. I shelled in remotely and got this info:
gandalf root # hdparm /dev/hde
/dev/hde:
multcount = 16 (on)
IO_support = 0 (default 16-bit)
unmaskirq = 0 (off)
using_dma = 1 (on)
keepsettings = 0 (off)
readonly = 0 (off)
readahead = 8 (on)
geometry = 155061/16/63, sectors = 156301488, start = 0
gandalf root # hdparm -tT /dev/hde
/dev/hde:
Timing buffer-cache reads: 1520 MB in 2.00 seconds = 760.00 MB/sec
Timing buffered disk reads: 106 MB in 3.00 seconds = 35.33 MB/sec
gandalf root #
He is on a fairly old kernel:
gandalf root # uname -a
Linux gandalf 2.4.22-aa1 #8 Mon Aug 9 16:50:41 PDT 2004 i686 AMD
Athlon(tm) XP 2500+ AuthenticAMD GNU/Linux
gandalf root #
and his grub.conf file:
default 2
timeout 20
splashimage=(hd0,1)/boot/grub/splash.xpm.gz
title=2.4.22-aa1
root (hd0,1)
kernel (hd0,1)/boot/bzImage-2.4.22-aa1 ro root=/dev/hde3 hdg=none
title=2.4.22-aa1-20040507
root (hd0,1)
kernel (hd0,1)/boot/bzImage-2.4.22-aa1-20040507 ro root=/dev/hde3 hdg=none
title=2.4.22-aa1-20040809
root (hd0,1)
kernel (hd0,1)/boot/bzImage-2.4.22-aa1-20040809 ro root=/dev/hde3 hdg=none
Don't know if any of this is going to help you so I'll shut up for now.
good luck,
Mark
I can give you more data for that box if it's helpful, but maybe I
need to better understand your setup.