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. -- Steve -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
