[PlanetCCRMA] about Fedora updates

Niels Mayer nielsmayer at gmail.com
Sat Mar 13 15:12:36 PST 2010

[[resending to list w/ over-100K-bounce-causing-log-paste replaced by URL to
complete logfile]]

Fernando -- Thank you for your help! I had long fixed the issues with
improper parameters to Jack, so your message forced me to revisit all my old
assumptions regarding CCRMA's Jack by re-adding CCRMA to my repos and
updating to
   jack-audio-connection-kit.i686 0:1.9.4-1.fc12.ccrma

  jack-audio-connection-kit.x86_64 0:1.9.4-1.fc12.ccrma

  jack-audio-connection-kit-example-clients.x86_64 0:1.9.4-1.fc12.ccrma

This Jack now starts correctly, but outputs a concerning error message;
however it works, and worked beautifully until it crashed along with
rosegarden in the "is it really realtime" part of my test. While running, it
gave fewer of those inconsequential Xruns that I get whenever I have jack
playing back music and decide to type an email message in gmail.

The concerning error message is "Cannot use real-time scheduling (RR/60)(1:
Operation not permitted) // AcquireSelfRealTime error" Prior, it says "JACK
server starting in realtime mode with priority 60."

Despite the error messages, I see the "RT" indicator flashing in the
qjackctl display, and even starting mythtv and simultaneously watching an HD
channel during music playback (something realtime intensive to test
nonrealtimeness of music playback) only causes **** alsa_pcm: xrun of at
least 0.666 msecs 13:39:04.515 XRUN callback (4)." once, when mythtv starts
up while Hydrogen is playing. A second run using Rosegarden 10 without all
the torture testing resulted in 0 x-runs and no crashes. I will continue
testing further w/ more audio intensive apps later (these were tests were
mostly MIDI, or one softsynth and sequencer, which is not very challenging).

Here's the results and logs from the first run that resulted in a crash, and
a second successful run with Rosegarden (with mythfrontend no longer running
and displaying off-air HD channel, and also with cpu scaling set to
"performance" mode). The first run had both mythtv playing and was running
in CPU "ondemand" mode (0.8G->3.4G CPU freq scaling) for maximum realtime
torture of Jack. (yes I realize cpu freq scaling isn't helpful to realtime


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