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
i tried it also with preemptoff and preemptirqsoff, with the same
result. the 'ftrace' tracer works as expected (ftrace is quite
impressive btw)
any clue what i am doing wrong?
--
Matthias Kaehlcke
Embedded Linux Engineer
Barcelona
Control over the use of one's ideas really constitutes control over other
people's lives; and it is usually used to make their lives more difficult.
(Richard Stallman)
.''`.
using free software / Debian GNU/Linux | http://debian.org : :' :
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