At this point, still writing my thesis. However, some development was made to lttng-tools.
In order to support lttng UST 2.0, we developed several efficient data structure to handle the applications, once registered, and the different UST domain (PID, exec name, global). The hashtable shrink code of the ht-shrink branch from URCU git tree was copied and used across the code to handle every UST data structure. RCU mechanism are used to ensure coherent data between the apps state and the client requests. Development is ongoing and basic UST support should be ready soon (by the end of October 2011). At this point, NO support for UST is ready in the git head or past releases.
Finally, lttng-tools pre14 was released with the addition of syscalls tracing support. You can now use --syscall with the enable event command. Note that enabling all events (-a) will enable syscall as well. We encountered some full tracing buffers after a very short period of time using -a -k. The default buffer size might increase in the next release. For now, I suggest you double the default size of buffers from 262144 to 524288 using:
# lttng enable-channel mychan -k --subbuf-size 524288
# lttng enable-event -a -k -c mychan
Thanks to all.