Re: [patch] voluntary-preempt-2.6.8-rc3-O5

Ingo Molnar
2004-08-11T07:30:50Z

* Lee Revell <rlrevell@joe-job.com> wrote:

> (jackd/12427): 10882us non-preemptible critical section violated 400
> us preempt threshold starting at kernel_fpu_begin+0x10/0x60 and ending
> at fast_clear_page+0x75/0xa0

to make sure this is a real latency and not some rdtsc weirdness, could
you try the latest version of preempt-timing:

http://redhat.com/~mingo/voluntary-preempt/preempt-timing-on-2.6.8-rc3-O5-A2

this adds jiffies-based latency values to the printout, e.g.:

(ksoftirqd/0/2): 3860us [3 jiffy] non-preemptible critical section
violated 100 us preempt threshold starting at ___do_softirq+0x1b/0x90
and ending at cond_resched_softirq+0x57/0x70

shows that a 10 jiffy (10 msec) latency happened - which matches the
rdtsc-based 3860 usecs value.

Ingo