[LAU] no. of periods vs. estimated spare time

Dan Muresan danmbox at gmail.com
Thu Jan 1 13:45:21 EST 2009


[posted before in qjackctl help forum, which seems inactive]

Hi, I am seeing xruns with jackd. I'm using a real-time kernel and
played with rtprio settings, sampling rate, number of periods, and
buffer sizes with little luck. I need some clarifications on how Jack is
supposed to behave.

1. What does qjackctl display in red? It's two numbers, like "3 (2635)",
but I have no clue what they are. The first number stays small, but the
number in parantheses increments like crazy.

2. I see lots of "delay of 11618 usecs exceeds estimated spare time of
11553.0 usecs; restart" messages. But the "estimated spare time" only
seems to depend on the number of frames per period (jackd -p argument).
So even if I increase the number of periods (jackd --nperiods argument)
insanely, I still get these "restarts" just as often.

This doesn't seem right -- with a larger n * bufsize, the restarts
should at least become less frequent, right?

I don't care at all about latency -- I just want continuous audio (and
preferably quiet operation). Is there a way to get rid of these warnings
(and the presumably harmful resets)?

Thanks,
Dan Muresan



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