[lttng-dev] No trace files are generated for UST

[Thibault, Daniel]

> De : Manikandan Govindaswamy [mailto:magov at vestas.com] 
> Envoyé : 6 décembre 2013 04:49
>
> Now I'm trying with ust examples : demo and easy-ust and I'm facing the same problem of no tracing is generated.
>
> Please find the sessiond log and the execution sequence as below for sample.
>
> I tried the same for demo and it looks the same behaviour
>
> root@/tmp/lttng-build-root/bin # ./lttng create
> Session auto-20131206-113744 created.
> Traces will be written in /root/lttng-traces/auto-20131206-113744
> root@/tmp/lttng-build-root/bin # ./lttng enable-event -u --all
> All UST events are enabled in channel channel0
> root@/tmp/lttng-build-root/bin # ./lttng start
> Tracing started for session auto-20131206-113744
> root@/tmp/lttng-build-root/bin # cd ../../
> root@/tmp # ./sample
> root@/tmp # cd - /tmp/lttng-build-root/bin
> root@/tmp/lttng-build-root/bin # ./lttng stop
> Waiting for data availability
> Tracing stopped for session auto-20131206-113744
> root@/tmp/lttng-build-root/bin # ./lttng destroy
> Session auto-20131206-113744 destroyed
> root@/tmp/lttng-build-root/bin # cd /
> root@/ # cd root/
> root@~ # ls lttng-traces
> root@~ # cd lttng-traces/
> root@~/lttng-traces # ls
> test-20131205-180744
> root@~/lttng-traces #

   That works fine on my system.  You sure lttng-traces/test-20131205-180744 has an empty ust/uid/1000/64-bit/channel0_0 file?

   Did you 'make install' lttng-ust?  liblttng-ust must be in the $PATH, so try to run sample like this during the session:

$ LD_PRELOAD=/usr/local/lib/liblttng-ust ./sample

   Otherwise, we'll take a look at the output of the make.  In lttng-ust/doc/examples/easy-ust:

$ gcc -I. -c -o tp.o -x c -D TRACEPOINT_CREATE_PROBES sample_component_provider.h
$ gcc -I. -c -o sample.o sample.c
$ gcc -o sample sample.o tp.o -ldl -llttng-ust

   (Here I chose to skip tp.c entirely: '-x c -D TRACEPOINT_CREATE_PROBES sample_component_provider.h' is equivalent to 'tp.c' in the tp.o gcc line)

Daniel U. Thibault
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