* Oestman, Fredrik ([email protected]) wrote: > Hi, > > > We're experimenting with tracing calls to the pthreads library using a > LD_PRELOAD-ed interposer library, which is instrumented with UST > tracepoints. In the startup phase, before the application has been > called, probes are being registered, and one by one the tracepoints > start emitting events. So some of the pthreads mutex motions of UST > itself are being traced along. > > What would be a good way of avoiding emitting events before the > application itself has started, specifically events related to UST > mutexes?
one way would be to implement mutexes within lttng-ust, so we would stop using the pthread mutexes. > The ust-ctl library appears to have a function ustctl_register_done(), > is that useful? No. This function is called by the session daemon when it has completed sending all commands to the application so its internal lttng-ust state matches that of the active tracing sessions. We need to be aware that a lttng-ust library can interact with up to 2 session daemons: one for the user, one for root. > (Is there an API documentation?) Or would it be better > to find out which mutexes belong to UST and filter them out? custom implementation of mutexes within lttng-ust sounds like the best approach. Thanks, Mathieu > By controlling our interposer library from within the application we > can avoid the problem, but we'd rather do without recompiling the > application, since it sort of would defeat the reason for using > LD_PRELOAD in the first place. > > > Cheers, > > Fredrik Östman > > > _______________________________________________ > lttng-dev mailing list > [email protected] > http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com _______________________________________________ lttng-dev mailing list [email protected] http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
