Re: [Fwd: Re: [patch] Real-Time Preemption, -RT-2.6.9-mm1-V0.4]

Paul Davis
2004-10-29T11:02:06Z

>but now it should be possible to prove that Jackd itself doesnt
>introduce latencies, via the userspace-atomicity mode feature in -V0.5.5
>:-) If that proves that the latencies dont occur in Jackd (and if it's
>not another, even higher prio thread that causes the delay) then we can
>pass the ball back to the kernel.

this is something i haven't mentioned. when running in RT mode, jackd
also runs a higher prio RT thread called the watchdog. it wakes every
5 seconds to check that the "main" thread is not stalled (i.e. a
client that is stuck in a loop) and kills everything if it
is. however, this thread's loop is incredibly simple (it checks and
resets a single int variable and goes back to sleep) that causing a
700usec delay would itself seem to me to be indicative of a
problem. do you agree?

--p