In <[EMAIL PROTECTED]>, on 06/09/2005
at 07:24 PM, Bill Fairchild <[EMAIL PROTECTED]> said:
>I am confused.
Be careful to distinguish between dispatching status and addressing
modes.
>Ed Jaffe says when in Xmem mode the home address space is charged
>for CPU time (he meant the home's current TCB). JES2 is always the
> home space in this situation. JES2 PCs into CAS in order to do an
>SVC 26.
No. JES2 issues an SVC 26 in one of its subtasks, SVC 26 does a PC and
code in the PC routine eventually posts a work queue for the CAS or
schedules an SRB into it. What happens after that is CAS processing,
regardless of the PASN or SASN. Eventually CAS will post or otherwise
wake up SVC 26 in the JES2 service subtask.
>So JES2 is now the home and primary but CAS is the secondary.
See above. There might be code that runs as part of the request and
sets PASN to CAS, but once CAS is dispatched then CAS is autonomous
and its addressing mode is unrelated to that of the code that posted
it.
>JES2 is still the home,
Not for the work done by CAS.
>Whatever work CAS and VLF do should be charged to JES2's TCB,
> shouldn't it?
Not without enclave processing.
Think of SVC 26 as a VTAM application that sends data to CAS. You'd
expect SVC 26, VTAM and CAS to rack up CPU time independently of each
other, even when CAS is doing work as the result of a message sent to
it by SVC 26.
JES2 service task->SVC 26<->cross memory code<->CAS
--
Shmuel (Seymour J.) Metz, SysProg and JOAT
ISO position; see <http://patriot.net/~shmuel/resume/brief.html>
We don't care. We don't have to care, we're Congress.
(S877: The Shut up and Eat Your spam act of 2003)
----------------------------------------------------------------------
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
