Michael Ost wrote: > On 10/10/2011 03:04 PM, Clemens Ladisch wrote: >> I guess I can rule out SMIs because those should happen even when there >> is one thread per core. > > Are these "System Management Interrupts"?
Yes. >> How big are the latencies you're seeing? They are not from being >> interrupted by another RR thread at the same priority (see "man >> sched_rr_get_interval")? > > We are wiring up the ftrace system in the kernel and cyclictest to find > out for certain. It's looking like it could be 10s of milliseconds, when > there is only 2.9 msecs to process (44.1k/128 samples). Tens of millisconds looks too long for a SMI. Anyway, the fact that the delays occur only when there is CPU contention points to the kernel scheduler. What is the time quantum that sched_rr_get_interval() returns for these threads? Regards, Clemens _______________________________________________ Linux-audio-dev mailing list [email protected] http://lists.linuxaudio.org/listinfo/linux-audio-dev
