El Mon, Oct 27, 2008 at 12:03:10PM -0400 Steven Rostedt ha dit:
>
> On Mon, 27 Oct 2008, Matthias Kaehlcke wrote:
>
> > hi,
> >
> > i'm trying to trace a possible latency issue using ftrace with a
> > 2.6.27 kernel on a x86 platform, but there seems to be something that
> > i'm missing
> >
> > i do the following:
> >
> > cat available_tracers
> > wakeup preemptirqsoff preemptoff irqsoff ftrace sched_switch none
> >
> > echo 0 > tracing_enabled
> >
> > echo irqsoff > current_tracer
> >
> > echo 1 > tracing_enabled
> >
> > <do stuff>
> >
> > echo 0 > tracing_enabled
> >
> > cat latency_trace
> > # tracer: irqsoff
> > #
> >
> > cat trace
> > # tracer: irqsoff
> > #
> > # TASK-PID CPU# TIMESTAMP FUNCTION
> > # | | | | |
> >
> > cat tracing_max_latency
> > -1
>
> # echo 0 > tracing_max_latency
>
> The -1 is a misnomer :-( The tracing_max_latency is unsigned so a -1
> is actually a really big number.
thanks for the fast and very helpfull answer, and also thanks for the
great tool!
--
Matthias Kaehlcke
Embedded Linux Engineer
Barcelona
Representation of the world, like the world itself, is
the work of men; they describe it from their own point
of view, which they confuse with the absolute truth
(Simone de Beauvoir)
.''`.
using free software / Debian GNU/Linux | http://debian.org : :' :
`. `'`
gpg --keyserver pgp.mit.edu --recv-keys 47D8E5D4 `-
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