[lttng-dev] beginner question

Julien Desfossez jdesfossez at efficios.com
Sat May 5 01:54:55 EDT 2012

> First of all, that worked. Thank you.
> So let's suppose I only want to track a handful of system calls, what's
> the most efficient way to filter out everything else?

You can't filter at the source for now, you need to trace all system
calls, so your filtering will be done at analysis time.
If you are using babeltrace, you can just use grep on the output.

For example :
babeltrace /path/to/your/trace | grep -E "sched_switch|sys_open"

I know that's not really pretty, but for now it is the only option.
Soon the full-fledged trace viewers will allow a cleaner way to filter
and eventually we'll be able to select exactly the syscalls we want.

Hope this helps,


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