Subject: Re: [linux-audio-user] xrun madness
From: cv223_AT_comcast.net
Date: Wed Oct 20 2004 - 16:34:40 EEST
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. 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 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.
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.
Joel
> It's been quite a while since I've heard of anyone using it, but what
> about running Benno's disk latency testing program on your raid drives
> and see what happens?
>
> Or does that no longer work with 2.6 kernels?
>
> When I worked with the tool it gave me very reasonable numbers vs.
> what I was seeing for xruns.
>
> Also, I don't think I remember you mentioning what desktop environment
> you are using, but even with my 2.6.9-rc2-mm4 type kernel I got lots
> of xruns under KDE, while Gnome was much better and fluxbox was, for
> me, the best. (measurably...)
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