The question really cannot be answered as posed, because it depends on the contention rate.
Looking only at path-length fastest to slowest: SETLOCK Latch ENQ But that is in the absence of contention. Once the requestor has to be suspended because of contention, you've lost. The Latch and ENQ approaches, being more granular, make it possible to have less contention as "no one else" can also be contending (unlike the local lock where any getmain or post or myriad other things being done in that space could also need the local lock). Latches have the benefit of not needing any other system serialization themselves to grant (again, in the absence of contention). I would be fairly certain that a complicated PLO operation (it takes a good deal of setup to issue even a simple PLO) with more-complex logic would lose out to SETLOCK and possibly even latch obtain when there is no contention. It will certainly make your code far harder to maintain (let alone to certify). PLO would likely be a winner if there is contention. Peter Relson z/OS Core Technology Design ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
