Hi
On 2016-09-16 07:43 AM, David Aldrich wrote:
Hi
I wonder if I might ask for some more guidance please?
I now have lttng and Trace Compass running on Ubuntu. I want to inspect the
scheduling of threads in my user-space application. So far, I have
successfully captured a trace with the sched_switch event enabled:
$ sudo lttng enable-event -k sched_switch
This indeed shows my app's threads. However, it also shows all the other
threads in the system and does not show clearly (to my understanding) when the
threads are scheduled / blocked.
I would like some guidance on how to improve this tracing.
1) Would it be better if I defined my own “tracepoint providers” and then set
trace events for when a thread wakes / blocks?
Could be a solution but you might want the built-in utility of lttng to
filter out all noise first using the filtering feature.
e.g I'm interested in sched_switch event where chrome is involved
lttng create
lttng enable-event --kernel "sched_switch" --filter 'prev_comm ==
"chrome*" || next_comm == "chrome*"'
lttng start
....
Using TraceCompass you will be mainly interested in the Control Flow
View and the Resource view (show per cpu timeline activity).
2) How could I show which core a thread is running on?
The Resource view from TraceCompass should help here.
Cheers
Best regards
David
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--
Jonathan R. Julien
Efficios
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