All timers are per-process except for the real time profile interval timer, which is per_LWP. See the setitimer(2) man page for a description of the ITIMER_REALPROF timer.
The timer IDs of per-process timers are usable from any LWP. The expiration signals are generated for the process rather than directed to a specific LWP.
The per-process timers are deleted only by timer_delete(3RT), or when the process terminates.