LTTng » LTTng-UST

While trying to create a trace with events only a single cpu I tried to used taskset and witnessed that lttng_ust_statedump events are sometimes missing.

I was able to reproduce this issue with the follow commands:

lttng create
lttng enable-event -a -u
lttng start
taskset -c 0 ~/lttng-tools/tests/utils/testapp/gen-ust-nevents/gen-ust-nevents 2
lttng stop
lttng view

When running those commands multiple times in loop I see lttng_ust_statedump events only 1 in 20 runs. All other runs only contain the event directly produced by the app. The lttng_ust_statedump should be emitted every time a UST app is launched.