Re: ftrace not working?

[KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>]

Hi

> I tried ftrace with the linus git 2.6.29 rc-6, & rc-8, but I always seem to
> get empty trace! Am I doing something wrong?
> 
> This is what I did.
> 
> linux-glcc:/data/git/linux-2.6 # cd /sys/kernel/debug/tracing/
> linux-glcc:/sys/kernel/debug/tracing # cat available_tracers 
> function_graph function sysprof sched_switch nop
> linux-glcc:/sys/kernel/debug/tracing # echo sched_switch > current_tracer 
> linux-glcc:/sys/kernel/debug/tracing # echo 1 > tracing_enabled 
> linux-glcc:/sys/kernel/debug/tracing # cat tracing_enabled 
> 1
> linux-glcc:/sys/kernel/debug/tracing # cat trace
> # tracer: sched_switch
> #
> #           TASK-PID    CPU#    TIMESTAMP  FUNCTION
> #              | |       |          |         |

your operation seems fine and your .config seems fine too.
but my box works ftrace well on 2.6.29-rc8.

hmm...

Could you post followin operation result and dmesg?

# cat failures
# cat current_tracer
# cat trace_options
# cat buffer_size_kb
# cat dyn_ftrace_total_info
# cat trace_options
# cat set_ftrace_filter
# cat tracing_cpumask
# cat tracing_enabled
# cat tracing_on