wakeup tracer not able to capture traces on 3.4 kernel

wakeup tracer not able to capture traces on 3.4 kernel

[Prabhat Kumar Ravi]

Hi,

I trying to capture traces through wakeup tracer, but not able to
capture it on 3.4 kernel with cortex A9 processor, armv7.
{{{
/ # mount -t debugfs nodev /debug
/ # sysctl kernel.ftrace_enabled=1
kernel.ftrace_enabled = 1
/ # echo wakeup > /debug/tracing/current_tracer
/ # echo latency-format > /debug/tracing/trace_options
/ # echo 0 > /debug/tracing/tracing_max_latency
/ # echo 1 > /debug/tracing/tracing_on
/ # sleep 10
/ # echo 0 > /debug/tracing/tracing_on
/ # cat /debug/tracing/trace
# tracer: wakeup
#
}}}

Please suggest me where I am wrong.

Regards,
Prabhat

Re: wakeup tracer not able to capture traces on 3.4 kernel

[Prabhat Kumar Ravi]

On Thu, Aug 29, 2013 at 7:41 PM, Prabhat Kumar Ravi
<prabhatravi09@gmail.com> wrote:
> Hi,
>
> I trying to capture traces through wakeup tracer, but not able to
> capture it on 3.4 kernel with cortex A9 processor, armv7.
> {{{
> / # mount -t debugfs nodev /debug
> / # sysctl kernel.ftrace_enabled=1
> kernel.ftrace_enabled = 1
> / # echo wakeup > /debug/tracing/current_tracer
> / # echo latency-format > /debug/tracing/trace_options
> / # echo 0 > /debug/tracing/tracing_max_latency
> / # echo 1 > /debug/tracing/tracing_on
> / # sleep 10
> / # echo 0 > /debug/tracing/tracing_on
> / # cat /debug/tracing/trace
> # tracer: wakeup
> #
> }}}

My target board is xilinx-zc702,
here in kernel/trace/trace.c:
void tracing_record_cmdline(struct task_struct *tsk)
{
if (atomic_read(&trace_record_cmdline_disabled) || !tracer_enabled ||
   !tracing_is_on())
-------------------------------> it not coming here at all.
return;

trace_save_cmdline(tsk);
}

Regards,
Prabhat

Re: wakeup tracer not able to capture traces on 3.4 kernel

[Prabhat Kumar Ravi]

Thanks to all, I got solution, this issue is due to lack of proper
timer implementation.

On Thu, Aug 29, 2013 at 8:42 PM, Prabhat Kumar Ravi
<prabhatravi09@gmail.com> wrote:
> On Thu, Aug 29, 2013 at 7:41 PM, Prabhat Kumar Ravi
> <prabhatravi09@gmail.com> wrote:
>> Hi,
>>
>> I trying to capture traces through wakeup tracer, but not able to
>> capture it on 3.4 kernel with cortex A9 processor, armv7.
>> {{{
>> / # mount -t debugfs nodev /debug
>> / # sysctl kernel.ftrace_enabled=1
>> kernel.ftrace_enabled = 1
>> / # echo wakeup > /debug/tracing/current_tracer
>> / # echo latency-format > /debug/tracing/trace_options
>> / # echo 0 > /debug/tracing/tracing_max_latency
>> / # echo 1 > /debug/tracing/tracing_on
>> / # sleep 10
>> / # echo 0 > /debug/tracing/tracing_on
>> / # cat /debug/tracing/trace
>> # tracer: wakeup
>> #
>> }}}
>
> My target board is xilinx-zc702,
> here in kernel/trace/trace.c:
> void tracing_record_cmdline(struct task_struct *tsk)
> {
> if (atomic_read(&trace_record_cmdline_disabled) || !tracer_enabled ||
>    !tracing_is_on())
> -------------------------------> it not coming here at all.
> return;
>
> trace_save_cmdline(tsk);
> }

 Regards,
 Prabhat