On 5/26/2016 2:51 PM, Charles Mills wrote:
1. Where is the original dispatching and limit priority for the jobstep task set? How do I determine (not with an API at runtime, but in advance with a command or looking at a parm member) what it is presumably going to be?
Sigh... the initial starting value varies by who attaches the jobstep task. And then any subsequent attaches in the task tree effect the value for the attached task.
The thing to remember is that the (task) minor priority is a tie-breaker between work (tasks and preemptable SRBs) running within a single address space. Between the work for two different address spaces it is irrelevant.
It's been over 20 years since I had to deal with problems in this area (MVS/ESA SP5.1), and I don't remember all the specifics. I know that jobsteps attached by the started task controller start with a minor priority of 255. I think the same is true of batch initiator jobs. I believe the TSO TMP attaches all commands with a minor priority of 250. And UNIX Systems Services did not exist at the time.
2. There are several references to a dispatching priority of zero. Does zero mean the subtask does not run at all, or just that it is last in line for a CPU?
A minor dispatching priority of 0 means it is last in line, *within* it's own address space, for being dispatched. It won't prevent it from running.
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