Subject: Re: [linux-audio-user] xrun madness
From: Mark Knecht (markknecht_AT_gmail.com)
Date: Wed Oct 20 2004 - 16:55:29 EEST
On Wed, 20 Oct 2004 13:34:40 +0000, cv223_AT_comcast.net <cv223_AT_comcast.net> wrote:
> Thanks for the reply, Mark.
>
> I ran Benno's disk latency tests quite a bit when I was setting up my system. As far as
> I could tell, the test just checks playback, not record.
I think you are right about that. Sorry. I had not considered that the
test program only checks read operation. I did understand that you
problem was write only.
> As I mentioned, I have no trouble playing back (in either Duplex or Playback modes) to either > disk system.
> When I was fussing with the early 2.6 kernels, performance with these tests was always > worse than with 2.4.23. With the 2.4.23 kernel, tests on the IDE/ATA drive
> were consistently < 3ms, whereas there were usually a couple >3ms blips with the SCSI
> Raid0 with the diskwrite and diskcopy stress tests (all other tests were <3ms). When I
> turned on the write cache on the SCSI drives, the results were like the IDE/ATA, but I got
> just as many xruns with jackd and ardour. This was one of the observations that made me > wonder whether the problem was actually the SCSI controller (i.e., nothing I did to the SCSI > system affected the number of xruns).
I don't suppose that your SCSI disk is suddenly getting more full, is
it? I just went through this on my 1394 drives under Pro Tools. Drives
are slower at the far end of the drive. You might be able to find your
SCSI drives at http://www.storagereview.com as they seem to cover SCSI
quite a bit. My 1394 drives got full and I suddenly started losing
lots of takes. Cleaned then out and the problems went away.
>
> I haven't tried those latency tests with the 2.6.9 that I have now, primarily because they
> didn't match up with the "real world" performance that I am concerned with (multitrack
> recording). This is why I'm hoping the ecasound tests will tell me something.
I'm interested to see what ecasound tells you.
>
> As for desktop, I'm using openbox - I got fewer xruns with it than with gnome. Never tried > KDE, but posts to this list (including yours!) don't encourage me to.
>
OK - was just checking.
- Mark
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