[lttng-dev] make a trace_event in a module (driver)

Francis Giraldeau francis.giraldeau at gmail.com
Sun Dec 15 17:54:06 EST 2013


Le 2013-12-15 13:22, Klaus Dannecker a écrit :
> Hello,
> 
> now its work!
> i have download the new lttng-tools. (git pull)
> 
> the next problem:
> with
> sudo insmod
> /lib/modules/3.8.0-29-generic/extra/addons/lttng-trace-events-sample.ko
> and
> lttng list -k
> hurray! i see the new event!

Great!

> now i start a lttng session and load the trace-events-sample.ko
> (compiling the sample in the linux source code)
> but i see not the event in the session. (looking in the eclipse viewer)
> what i am doing wrong?

Could it be possible that the tracepoint is not called? To verify this,
I would recommend you to display the information in dmesg just before
the tracepoint:

if (printk_ratelimit())
	printk("hello event!");

Then: dmesg -c

What does exactly the module is supposed to record?

Cheers,

Francis



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