<snip>
The code snippets I posted show that the code sleeps rather than waiting 
to be signaled which I suspect may be cheaper on those platforms.
</snip>
I don't know about the relative cheapness, but generally sleeping (and 
looking again when you wake up) is easier, and waiting/posting 
(pausing/releasing) is more responsive.

<snip>
This is quite common in the assembler code I see. A CS loop with a timer 
</snip>
I presume you mean a CS loop that continues to loop even if the starting 
condition does not change, but after a while sleeps.

<snip>
Is "priority inversion" not an issue on z/OS. I know that swapped out 
address spaces go to the top of the dispatcher queue but
how does it work for tasks?
</snip>
Of course it's an issue. In some cases, the operating system can help. In 
others, the (authorized) application must do it. I say "authorized" 
because priority inversions in z/OS are typically multi-address-space 
issues, because the default for tasks in an address space is that they all 
run at the same priority.

<snip>
You can call CHAP. 
</snip>
You can call it but it won't in general do anything to help a priority 
inversion case, unless it's to help a problem that you introduced by 
previous use of CHAP. CHAP is for creating your own intra-address space 
priorities. 

Peter Relson
z/OS Core Technology Design


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