ttp://mason.gmu.edu/~smetz3
From: IBM Mainframe Discussion List [IBM-MAIN@LISTSERV.UA.EDU] on behalf of
Brian Westerman [brian_wester...@syzygyinc.com]
Sent: Sunday, July 16, 2023 2:39 AM
To: IBM-MAIN@LISTSERV.UA.EDU
Subject: Re: A question about CPU usage on z
Everything in a wait is not "eligible" to run. That's pretty much the
definition of wait. :)
Brian
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: A question about CPU usage on z/OS
Every address space has multiple TCB. Only TCBs that are not in a wait
(dispatchable) are eligible to run on separate CPUs. You are correct but all
TCBs in a wait are not eligible to run.
On Friday, July 14, 2023 at 05:56:58 PM PDT, Brian Westerman
wrote
: IBM Mainframe Discussion List on
> behalf of Jon Perryman > Sent: 15 July 2023 05:54 > To:
> IBM-MAIN@LISTSERV.UA.EDU > Subject: Re: A question about CPU usage on z/OS >
> > While each cpu in the 504 is slower than a 701 cpu, running 4 batch jobs at
> the same time s
on behalf of Jon
Perryman
Sent: 15 July 2023 05:54
To: IBM-MAIN@LISTSERV.UA.EDU
Subject: Re: A question about CPU usage on z/OS
While each cpu in the 504 is slower than a 701 cpu, running 4 batch jobs at the
same time should reduce run time because each batch job expect reduced wai
is approx 12% of
the 701
Regards
Parwez Hamid​
From: IBM Mainframe Discussion List on behalf of Jon
Perryman
Sent: 15 July 2023 05:54
To: IBM-MAIN@LISTSERV.UA.EDU
Subject: Re: A question about CPU usage on z/OS
While each cpu in the 504 is slower than a 701
While each cpu in the 504 is slower than a 701 cpu, running 4 batch jobs at
the same time should reduce run time because each batch job expect reduced wait
because there is reduced competition for the CPU. However, you could be correct
if the 4 batch jobs are experiencing heavy I/O wait.
Every address space has multiple TCB. Only TCBs that are not in a wait
(dispatchable) are eligible to run on separate CPUs. You are correct but all
TCBs in a wait are not eligible to run.
On Friday, July 14, 2023 at 05:56:58 PM PDT, Brian Westerman
wrote:
I'm pretty sure that each
On 7/14/2023 3:01 PM, Jon Perryman wrote:
> As for batch running slower at night after you went from 1 CPU to 4,
that doesn't make sense unless other things changed.
I'm thinking it could be as simple as say, going from a 701 to a 504.
The overall MIPS are bumped up, multi-task address spaces
I'm pretty sure that each TCP of a task can run on a separate CPU.
Brian
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a hundred
tasks with over 10 dispatchable tasks at one time. All could be active as long
as enough CPUs are available.On Wednesday, July 12, 2023 at 03:27:32 PM
PDT, Jason Cai wrote:
Dear all,
I have a question about CPU usage on z/OS that I hope you can help me with.
Many years ago, we
CPU Affinity has not been supported for many years.
I don't remember if it ever was on an address-space basis as opposed to begin
on a work-unit basis (I know that you could identify CPU affinity for a
scheduled SRB, for example).
The "multiprocessor effect" (or perhaps it's the
List On Behalf Of
Seymour J Metz
Sent: Thursday, July 13, 2023 12:07 AM
To: IBM-MAIN@LISTSERV.UA.EDU
Subject: [EXTERNAL] Re: A question about CPU usage on z/OS
A task can only use one CPU at a time, but MVS has never limited an address
space to a single CPU except for the case of CPU affinity
://mason.gmu.edu/~smetz3
From: IBM Mainframe Discussion List [IBM-MAIN@LISTSERV.UA.EDU] on behalf of
Jason Cai [ibmm...@foxmail.com]
Sent: Wednesday, July 12, 2023 6:27 PM
To: IBM-MAIN@LISTSERV.UA.EDU
Subject: A question about CPU usage on z/OS
Dear all,
I
> From: IBM Mainframe Discussion List On Behalf
> Of Jason Cai
> Sent: Wednesday, July 12, 2023 5:27 PM
> To: IBM-MAIN@LISTSERV.UA.EDU
> Subject: [EXTERNAL] A question about CPU usage on z/OS
>
> Dear all,
>
> I have a question about CPU usage on z/OS that I hope you can help m
: Wednesday, July 12, 2023 5:27 PM
To: IBM-MAIN@LISTSERV.UA.EDU
Subject: [EXTERNAL] A question about CPU usage on z/OS
Dear all,
I have a question about CPU usage on z/OS that I hope you can help me with.
Many years ago, we increased the CPU of a mainframe from one to four, but the
batch jobs at night
Dear all,
I have a question about CPU usage on z/OS that I hope you can help me with.
Many years ago, we increased the CPU of a mainframe from one to four, but the
batch jobs at night became slower. The explanation at that time was that a
batch job could only use one CPU, and the single CPU
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