[lttng-dev] lttng-ust missing tracepoints
gerlando.falauto at keymile.com
Thu May 15 13:39:42 EDT 2014
I created a simple tracepoint following the examples within lttng-ust
documentation. The .C source (travcepoint provider) and header files are
generated by means of the lttng-gen-tp helper script and then compiled
and linked manually within the application.
However, my tracepoints are not displayed.
I start tracing with the usual sequence:
lttng enable-event -u -a --loglevel=TRACE_DEBUG
I also tried double checking:
# lttng list auto-19700101-003803
Tracing session auto-19700101-003803: [inactive]
Trace path: /root/lttng-traces/auto-19700101-003803
=== Domain: UST global ===
Buffer type: per UID
- channel0: [enabled]
overwrite mode: 0
subbufers size: 131072
number of subbufers: 4
switch timer interval: 0
read timer interval: 0
* (loglevel <= TRACE_DEBUG (14)) (type: tracepoint) [enabled]
I thoroughly checked the instructions at
and everything looks correct to me.
I also doubled checked that the code gets indeed compiled and linked
correctly (i.e. make is not playing nasty tricks on me).
If I put an additional tracef() call exactly where my tracepoint is
located, this gets traced without a problem. So the infrastructure
should be all working in my opinion.
What I find weird is that if I purposedly make a mistake within
TRACEPOINT_LOGLEVEL() (e.g. wrong provider or tracepoint name), I get no
complaint from the compiler or linker.
The initial value was TRACE_WARNING, I also tried removing that part
altogether, everything to no avail. tracef() keeps working fine though.
I also checked the compiler, it's gcc, not g++ (though the application
using it is indeed compiled with g++). I double checked on both arm and
powerpc (in both cases it's always about cross-compiling).
What could I be missing?
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