Re: [PATCH] [request for inclusion] Realtime LSM

[Jack O'Quin]

>> * Jack O'Quin <joq@xxxxxx> wrote:
>>> One major problem: this `nice --20' hack affects every thread, not
>>> just the critical realtime ones.  That's not what we want.  Audio
>>> applications make very conscious choices which threads run with high
>>> priority and which do not.

> Ingo Molnar <mingo@xxxxxxx> writes:
>> how much did this problem affect your test? Could the source of the 500
>> msec delays be the non-highprio components of the test that somehow
>> became nice --20?

Jack O'Quin <joq@xxxxxx> writes:
> Probably, the best way to tell would be patching JACK so it uses
> nice(-20) instead of pthread_setschedparam() for the realtime threads.
> As a hack, that looks easy.  I'll build a working directory with just
> that change, so we can experiment with it better.

Bah!  Nothing is ever as easy as it looks.

According to the manpage, nice(2) is per-process not per-thread.  That
does not give the granularity we need.  

Is that correct?  If so, I can't think of any way to make this work.
Suggestions?

We need to allow both realtime and non-realtime threads in the same
process.  Anything less would require an enormous rewrite for most
audio programs, an unreasonable thing to ask.
-- 
  joq
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