[lttng-dev] Beginner question: how to inspect scheduling of multi-threaded user application?

[Francis Deslauriers]

Hi David,
If you specifically want to trace the scheduling of the threads of your
app, you don't need custom tracepoints.
Enabling the sched_switch kernel event will give you both of cpu id and
thread id. Look at the cpu_id and next_tid fields.

You can enable the sched_switch event using : lttng enable-event -k
sched_switch

Cheers,
Francis

2016-08-24 3:17 GMT-04:00 David Aldrich <David.Aldrich at emea.nec.com>:

> Hi
>
>
>
> I am new to tracing in Linux and to lttng. I have a multi-threaded user
> application and I want to see:
>
>
>
> 1)      When the threads are scheduled to run
>
> 2)      Which cores the threads are running on.
>
>
>
> I have installed lttng on Ubuntu 14.04 LTS.  I am expecting to visualise
> the trace using TraceCompass.
>
>
>
> I have read the following doc section:
>
>
>
> http://lttng.org/docs/#doc-tracing-your-own-user-application
>
>
>
> In order to collect my trace, must I define custom tracepoint definitions ( in
> a tracepoint provider header file ), and insert tracepoints into my user
> application, or is there a simpler way of achieving my goal?
>
>
>
> Best regards
>
>
>
> David
>
>
>
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>
>
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