tree a3d92846e1a09a829f300ab15726ee9c288cb49e
parent a0a70c735ef714fe1b6777b571630c3d50c7b008
author Török Edwin <edwintorok@gmail.com> 1227353327 +0200
committer Ingo Molnar <mingo@elte.hu> 1227428715 +0100

tracing: add support for userspace stacktraces in tracing/iter_ctrl

Impact: add new (default-off) tracing visualization feature

Usage example:

 mount -t debugfs nodev /sys/kernel/debug
 cd /sys/kernel/debug/tracing
 echo userstacktrace >iter_ctrl
 echo sched_switch >current_tracer
 echo 1 >tracing_enabled
 .... run application ...
 echo 0 >tracing_enabled

Then read one of 'trace','latency_trace','trace_pipe'.

To get the best output you can compile your userspace programs with
frame pointers (at least glibc + the app you are tracing).

Signed-off-by: Török Edwin <edwintorok@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>