plockstat Reader/Writer Lock Probes

Reader/writer locks enable multiple readers or a single writer, but not both, to be in a critical section at one time. These locks are typically used for structures that are searched more frequently than they are modified, or when threads spend substantial time in a critical section. Users interact with reader/writer locks using the Oracle Solaris rwlock or POSIX pthread_rwlock_init interfaces.

The probes pertaining to readers/writer locks are described in the following list. For each probe, arg0 contains a pointer to the rwlock_t or pthread_rwlock_t structure that represents the adaptive lock. arg1 contains a boolean value that indicates whether the operation was as a writer.

rw-acquire

Hold event probe that fires immediately after a readers/writer lock is acquired.

rw-block

Contention event probe that fires before a thread blocks while attempting to acquire a lock. If enabled, the rw-acquire probe or the rw-error probe will fire after rw-block.

rw-error

Error event probe that fires when an error is encountered during a reader/writer lock operation. arg1 is the errno value of the error encountered.

rw-release

Hold event probe that fires immediately after a reader/writer lock is released.