Re: [patch] voluntary-preempt-2.6.8.1-P0

Ingo Molnar
2004-08-16T02:42:03Z

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

> http://krustophenia.net/testresults.php?dataset=2.6.8.1-P0

nice. (What is the difference between the left-hand and the right-hand
graphs - why is the right-hand side one 'wider'?)

> The peaks on this graph should correspond directly to the length of
> the non-preemptible critical section reported by Ingo's latency
> tracer. I think the large peak around 580-600usecs is caused by the
> extract_entropy issue (which can be hit by regular processes and
> ksoftirqd), and the large peak around 80-100 by the XFree86 unmap_vmas
> issue, as the times match and these are by far the most common
> reported in latency_trace.

just to check this theory, could you make __check_and_rekey() an empty
function? This should still produce a working random driver, albeit at
much reduced entropy. If these latencies have a relationship to the
mlockall() issue then this change should have an effect.

Ingo