"You can use the enque/delay_max, enque/delay_max_refine and enque/delay_jitter parameters to control how long the system waits if _WAIT is specified. If a lock request is rejected, the application tries at most five times (default setting for enque/delay_max) about once a second (default setting for enque/delay_max_refine) to set the lock. The lock is requested only "approximately" each second to avoid that request of parallel processes are made at exactly the same time. The exact time between the attempts varies randomly in a range of +/- 400 ms (default setting for enque/delay_jitter). The lock requests are made in a time interval of 0.6 to 1.4 seconds. You should not change then enque/delay_max parameter.