[linux-audio-user] realtime-preempt-2.6.11-rc1-V0.7.35-01

Eric Dantan Rzewnicki eric at zhevny.com
Sun Jan 16 18:38:39 EST 2005


Jack O'Quin wrote:
> Eric Dantan Rzewnicki <eric at zhevny.com> writes:
>>jackd starts fine like this:
>>LD_ASSUME_KERNEL=2.4.22 jackd -v -R -P 90 -d alsa -d ice1712 -p 64 -n 2
>>no xruns except the expected ones on client connect/disconnect. Does
>>it matter which version of 2.4 is assumed? I've seen .22 and .19 in
>>various places.
> Either is fine.  It forces glibc to use the old-style kernel
> interfaces for threading, so it to uses linuxthreads instead of NPTL.
>>there are 5 jackd threads started. Only one has prio 90 as specified
>>with -P. It and 2 others are SCHED_FIFO, but the 2 other are prio
>>99. How did they get that?  The remaining 2 threads are SCHED_OTHER
>>with prio 0. Is this expected behavior?
> Yes.  The other two realtime threads are the JACK watchdog timer and
> the Linuxthreads manager thread.

good. thanks for confirming.

>>I can run this script:
>>http://zhevny.com/bin/ecamynthes/ecanoscl-i-0.0.2.sh
>>which now starts ecasound like this:
>>chrt -f -p 80 ecasound <various_options>
>>and sets LD_ASSUME_KERNEL
> You should probably set LD_ASSUME_KERNEL consistently for all clients,
> but the `chrt' should not be necessary.  JACK will set all the client
> process thread priorities to 89 (one less than 90), IIRC.  You don't
> want to mess with the other ecasound threads.  They'll just interfere.

Ah! ok

but, ecasound doesn't get SCHED_FIFO that way, no?
(ecasound running w/pid 3764)
eric at audiobox:~$ chrt -p 3764
pid 3764's current scheduling policy: SCHED_OTHER
pid 3764's current scheduling priority: 0

or does ecasound's jack thread run inside jackd and not show up in ps 
output?



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