Thread locks are a special kind of spin lock that are used to
lock a thread for purposes of changing thread state. Thread lock hold events
are available as spin lock hold-event probes (that is, spin-acquire and spin-release), but
contention events have their own probe specific to thread locks. The thread lock
hold-event probe is in Table 18-3.
Table 18-3 Thread Lock Probe
Contention-event probe that fires after a thread has
spun on a thread lock. Like other contention-event probes, if both the contention-event
probe and the hold-event probe are enabled, thread-spin will fire before spin-acquire. Unlike other
contention-event probes, however, thread-spin fires before the lock is actually acquired. As a result,
multiple thread-spin probe firings may correspond to a single spin-acquire probe firing.