Re: 2.6.14-rc5-rt3 - `IRQ 8'[798] is being piggy

[Ingo Molnar <mingo@elte.hu>]

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

> On Fri, 2005-10-21 at 15:25 -0700, Mark Knecht wrote:
> > >
> > > No I don't think so.  CONFIG_RTC_HISTOGRAM is a hack, designed to work
> > > with a specific test program that runs SCHED_FIFO and poll()s on the
> > > RTC.  VLC apparently poll()s on the RTC but does not run SCHED_FIFO.  So
> > > of course there will be delays.
> 
> > Lee,
> >    Indeed, you are correct. Apparently under character devices I had
> > turned on the RTC histogram feature. With that off I am not only
> > getting the maximum latency values we expect.
> > 
> >    Now I'll have to let it run for hours/days to see if I catch any
> > info on these xruns, should I get another rash of them. Yesterday they
> > came only after about 14 hours of work. I had none the previous two
> > days.
> 
> In general you should avoid enabling/disabling random config options 
> between runs.  If you keep changing the .config it makes it impossible 
> to hunt bugs or compare one set of results to another.

i think i'll remove the CONFIG_RTC_HISTOGRAM feature altogether from the 
-rt tree - meanwhile we've got more advanced (and less verbose) latency 
histogram features via WAKEUP_LATENCY_HIST, PREEMPT_OFF_HIST and 
INTERRUPT_OFF_HIST.

	Ingo