11 Oct
2011
11 Oct
'11
10:23 a.m.
Michael Ost wrote:
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
On 10/10/2011 03:04 PM, Clemens Ladisch wrote:
Yes.
I guess I can rule out SMIs because those should
happen even when there
is one thread per core.
Are these "System Management Interrupts"? 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).