Re: [patch] Real-Time Preemption, -RT-2.6.9-rc4-mm1-U5

[Ingo Molnar]

* Adam Heath <doogie@xxxxxxxxxx> wrote:

> On Mon, 18 Oct 2004, Ingo Molnar wrote:
> 
> > > However, after I reset the threshold to 50(and got a few small traces), I got
> > > this whopper.
> > >
> > > (XFree86/1129/CPU#0): new 4692 us maximum-latency critical section.
> > >  => started at timestamp 358506933: <call_console_drivers+0x76/0x140>
> > >  =>   ended at timestamp 358511625: <finish_task_switch+0x43/0xa0>
> > >  [<c0132480>] sub_preempt_count+0x60/0x90
> >
> > interesting - this could be a printk (trace) done in a critical section
> > though. What does /proc/latency_trace tell, is it full of console code
> > functions?
> 
> Too late, it's gone.  It'd be nice if there was some way to have
> history on that file.

well - if it's gone it's always replaced by a larger latency (if you use
the preempt_max_latency method), which in most cases is more interesting
than the one you wanted to save.

	Ingo
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