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

[Jack O'Quin]

Ingo Molnar <mingo@xxxxxxx> writes:

> * Jack O'Quin <joq@xxxxxx> wrote:
>
>> OK, I reran with just 5 processes reniced from -10 to -5.  On my
>> system they were: events, khelper, kblockd, aio and reiserfs.  In
>> addition, I reniced loop0 from -20 to -5.
>
>> 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.
>
> 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?

Some interference is definitely possible.  But, the test does not
involve any graphical interface, so I'd expect that to be small.
Looking at jack_test3_client.cpp, the main thread just does a sleep()
while the process cycle is running.

Still, it's hard to be sure.  

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.
-- 
  joq
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