Xruns, but only when transport is stopped

[fourfour]

I've been trying this jackd configuration with Qtractor:

/usr/bin/jackd -P1 -p128 -dalsa -r96000 -p128 -n2 -D -Chw:0 -Phw:0 -o2

With the transport in play mode, I went 3.5 hours with out a single xrun. In contrast, when the transport is stopped, I get numerous constant xruns. Is this caused by my configuration? I don't understand why there should be such a large difference between the stopped and playing states.

[Pablo]

I don't understand why there should be such a large difference between the stopped and playing states.

Neither do I but I suggest you should increase the priority or just omit the -P flag. Afaik, the default is 10. Also, if possible, increase the period size.

[AutoStatic]

-P1 means the lowest priority possible. Try setting it higher, like 70. And what kind of soundcard are you using?

[fourfour]

I have been using the -P1 flag so that jackd will run in real-time. The sound card I'm using is an Echo Indigo IOx.

[tripomatic]

You should use the option -R to enable running in realtime.
The P flag is to give realtime priorities.
And 1 is very low.

Check out
$ man jackd

[Pablo]

You should use the option -R to enable running in realtime.

No, it is not needed. realtime is true by default.