Re: How to reduce the overhead of WLM?

[Allan Staller]

Classification: Confidential

1) reduce the number of service class periods and service classes
2) reduce the numberf of workloads
3) set CICS MAXTASKS to a reasonable number
4) Since this is a development system, set your major subsystems to velocity 
goals, not transaction goals (IMS, CICS, DB2, MQ)

This is a combination of experience and remembrance from a WLM training class.

Most people try to over-control WLM instead of letting it do its thing.\

HTH,


-Original Message-
From: IBM Mainframe Discussion List  On Behalf Of 
Wendell Lovewell
Sent: Monday, March 4, 2024 5:08 PM
To: IBM-MAIN@LISTSERV.UA.EDU
Subject: How to reduce the overhead of WLM?

[CAUTION: This Email is from outside the Organization. Unless you trust the 
sender, Don’t click links or open attachments as it may be a Phishing email, 
which can steal your Information and compromise your Computer.]

This is probably a strange question, but is there a way to reduce WLM cpu 
usage?   Here's the situation:

- The system is a lightly used development system.  Unless something is in a 
loop (very rare), CPU % probably is usually less than 10%.  And except for 
system regions & CICS, it's rare to have multiple jobs running concurrently.
- Only one processor defined to the VM. No ZIIP either.
- We are charged for CPU cycles.
- WLM is the highest consumer of CPU.  JES2, TCPIP, ZFS and SDSFAUX round out 
the top 5 consumers.

There is a lot of information about WLM tuning, but as best I can tell almost 
none of it relates to reducing WLM usage.

From reading the Init & Tuning manual, I'm trying these settings:
AIMANAGEMENT=NO
HIPERDISPATCH=NO
CCCAWMT=45
RMPTTOM=15000

I was thinking that perhaps reducing whatever processing intervals I could 
might help.  But I can't tell these changes made a difference.  (I don't have a 
tool to measure WLM usage.)

Any suggestions would be appreciated.

TIA,

Wendell

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Re: How to reduce the overhead of WLM?

[Anthony Hirst]

If you are running a lot of CICS regions, you might want to look at
reducing the mastask values, my understanding is that WLM create's PB for
every possible active task in CICS and they get scanned every 250 ms too.

On Mon, Mar 4, 2024 at 10:15 PM Jim Mulder  wrote:

>   The most important thing is RMPTTOM for reducing the SRM timer pop
> overhead.
> Note that Timer DIE processing is uncaptured time.
>
>   My IEAOPTxx  for running under  VM  has
>
> RMPTTOM=3 /*REDUCE SRM INVOKATION FREQUENCY ON VM */
>
>   And that is a value we set a couple of decades ago, and haven't thought
> much about it since.
> You might want it even higher for faster machines than we had back then.
>
>   I suggested some years ago that SRM should self-tune the timer pop
> interval to be less frequent at low utilization, but I haven't gotten any
> traction on that so far..
>
> Jim Mulder
>
>
> -Original Message-
> From: IBM Mainframe Discussion List  On Behalf
> Of Wendell Lovewell
> Sent: Monday, March 4, 2024 6:08 PM
> To: IBM-MAIN@LISTSERV.UA.EDU
> Subject: How to reduce the overhead of WLM?
>
> This is probably a strange question, but is there a way to reduce WLM cpu
> usage?   Here's the situation:
>
> - The system is a lightly used development system.  Unless something is in
> a loop (very rare), CPU % probably is usually less than 10%.  And except
> for system regions & CICS, it's rare to have multiple jobs running
> concurrently.
> - Only one processor defined to the VM. No ZIIP either.
> - We are charged for CPU cycles.
> - WLM is the highest consumer of CPU.  JES2, TCPIP, ZFS and SDSFAUX round
> out the top 5 consumers.
>
> There is a lot of information about WLM tuning, but as best I can tell
> almost none of it relates to reducing WLM usage.
>
> From reading the Init & Tuning manual, I'm trying these settings:
> AIMANAGEMENT=NO
> HIPERDISPATCH=NO
> CCCAWMT=45
> RMPTTOM=15000
>
> I was thinking that perhaps reducing whatever processing intervals I could
> might help.  But I can't tell these changes made a difference.  (I don't
> have a tool to measure WLM usage.)
>
> Any suggestions would be appreciated.
>
> TIA,
>
> Wendell
>
> --
> For IBM-MAIN subscribe / signoff / archive access instructions, send email
> to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
>
> --
> For IBM-MAIN subscribe / signoff / archive access instructions,
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Re: How to reduce the overhead of WLM?

[Allan Staller]

Classification: Confidential

Agreed!


-Original Message-
From: IBM Mainframe Discussion List  On Behalf Of 
Anthony Hirst
Sent: Tuesday, March 5, 2024 7:18 AM
To: IBM-MAIN@LISTSERV.UA.EDU
Subject: Re: How to reduce the overhead of WLM?

[CAUTION: This Email is from outside the Organization. Unless you trust the 
sender, Don’t click links or open attachments as it may be a Phishing email, 
which can steal your Information and compromise your Computer.]

If you are running a lot of CICS regions, you might want to look at reducing 
the mastask values, my understanding is that WLM create's PB for every possible 
active task in CICS and they get scanned every 250 ms too.

On Mon, Mar 4, 2024 at 10:15 PM Jim Mulder  wrote:

>   The most important thing is RMPTTOM for reducing the SRM timer pop
> overhead.
> Note that Timer DIE processing is uncaptured time.
>
>   My IEAOPTxx  for running under  VM  has
>
> RMPTTOM=3 /*REDUCE SRM INVOKATION FREQUENCY ON VM */
>
>   And that is a value we set a couple of decades ago, and haven't
> thought much about it since.
> You might want it even higher for faster machines than we had back then.
>
>   I suggested some years ago that SRM should self-tune the timer pop
> interval to be less frequent at low utilization, but I haven't gotten
> any traction on that so far..
>
> Jim Mulder
>
>
> -Original Message-
> From: IBM Mainframe Discussion List  On
> Behalf Of Wendell Lovewell
> Sent: Monday, March 4, 2024 6:08 PM
> To: IBM-MAIN@LISTSERV.UA.EDU
> Subject: How to reduce the overhead of WLM?
>
> This is probably a strange question, but is there a way to reduce WLM cpu
> usage?   Here's the situation:
>
> - The system is a lightly used development system.  Unless something
> is in a loop (very rare), CPU % probably is usually less than 10%.
> And except for system regions & CICS, it's rare to have multiple jobs
> running concurrently.
> - Only one processor defined to the VM. No ZIIP either.
> - We are charged for CPU cycles.
> - WLM is the highest consumer of CPU.  JES2, TCPIP, ZFS and SDSFAUX
> round out the top 5 consumers.
>
> There is a lot of information about WLM tuning, but as best I can tell
> almost none of it relates to reducing WLM usage.
>
> From reading the Init & Tuning manual, I'm trying these settings:
> AIMANAGEMENT=NO
> HIPERDISPATCH=NO
> CCCAWMT=45
> RMPTTOM=15000
>
> I was thinking that perhaps reducing whatever processing intervals I
> could might help.  But I can't tell these changes made a difference.
> (I don't have a tool to measure WLM usage.)
>
> Any suggestions would be appreciated.
>
> TIA,
>
> Wendell
>
> --
> For IBM-MAIN subscribe / signoff / archive access instructions, send
> email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
>
> --
> For IBM-MAIN subscribe / signoff / archive access instructions, send
> email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
>

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for the named recipient(s) only. E-mail transmission is not guaranteed to be 
secure or error-free as information could be intercepted, corrupted, lost, 
destroyed, arrive late or incomplete, or may contain viruses in transmission. 
The e mail and its contents (with or without referred errors) shall therefore 
not attach any liability on the originator or HCL or its affiliates. Views or 
opinions, if any, presented in this email are solely those of the author and 
may not necessarily reflect the views or opinions of HCL or its affiliates. Any 
form of reproduction, dissemination, copying, disclosure, modification, 
distribution and / or publication of this message without the prior written 
consent of authorized representative of HCL is strictly prohibited. If you have 
received this email in error please delete it and notify the sender 
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Re: How to reduce the overhead of WLM?

[Tom Marchant]

Would it help to have more of those address spaces in SYSSTC so that WLM 
doesn't try to manage them?

-- 
Tom Marchant

On Tue, 5 Mar 2024 01:03:27 +, Graham Harris  wrote:

>A few years back, I did a deep dive into tuning CPU usage across a
>multitude of very small z/OS guests under z/VM, and WLM was certainly a big
>hitter for many of them, but as there were so many instances, I was able to
>see notable differences in WLM use between "LPARs", which was obviously "of
>interest".
>The upshot seemed to be that WLM costs had a fairly firm relationship with
>the number of active address spaces on the "LPAR", presumably down to the
>amount of sampling that WLM has to do against each address space every
>250ms (I think).  I did enquire of IBM as to whether the sampling rate
>could be "adjusted", and that came back with a negative response (not
>really a surprise).
>So the obvious answer may be to only have address spaces started, when they
>are only really needed to be there.
>Although you may need to assess the cost of stopping/starting those address
>spaces, versus the background WLM cost.
>
>
>On Mon, 4 Mar 2024 at 23:08, Wendell Lovewell <
>01e9c0ee0673-dmarc-requ...@listserv.ua.edu> wrote:
>
>> This is probably a strange question, but is there a way to reduce WLM cpu
>> usage?   Here's the situation:
>>
>> - The system is a lightly used development system.  Unless something is in
>> a loop (very rare), CPU % probably is usually less than 10%.  And except
>> for system regions & CICS, it's rare to have multiple jobs running
>> concurrently.
>> - Only one processor defined to the VM. No ZIIP either.
>> - We are charged for CPU cycles.
>> - WLM is the highest consumer of CPU.  JES2, TCPIP, ZFS and SDSFAUX round
>> out the top 5 consumers.
>>
>> There is a lot of information about WLM tuning, but as best I can tell
>> almost none of it relates to reducing WLM usage.
>>
>> From reading the Init & Tuning manual, I'm trying these settings:
>> AIMANAGEMENT=NO
>> HIPERDISPATCH=NO
>> CCCAWMT=45
>> RMPTTOM=15000
>>
>> I was thinking that perhaps reducing whatever processing intervals I could
>> might help.  But I can't tell these changes made a difference.  (I don't
>> have a tool to measure WLM usage.)
>>
>> Any suggestions would be appreciated.
>>
>> TIA,
>>
>> Wendell
>>
>> --
>> For IBM-MAIN subscribe / signoff / archive access instructions,
>> send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
>>
>
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Re: TELNET PROFILE, strictly PDS?

[Radoslaw Skorupka]

W dniu 04.03.2024 o 20:29, Wendell Lovewell pisze:

As Allan said, you can compress an in-use PDS using IEBCOPY.

//CMPEXEC  PGM=IEBCOPY
//SYSPRINT DD  SYSOUT=*
//SYSUT3   DD  UNIT=SYSDA,SPACE=(CYL,(90))
//SYSUT4   DD  UNIT=SYSDA,SPACE=(CYL,(90))
//INDD0DD  DISP=SHR,DSN=&YOURPDS
//SYSINDD *
 C I=INDD0,O=INDD0
/*

You might have to adjust the SYSUT3/4 space.


My advice: use contemporary REGION and get rid of both SYSUT3/4 ddnames.
Especially for small datasets like TCPPARM.


--
Radoslaw Skorupka
Lodz, Poland

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Re: 35th International Rexx Symposium in Birsbane (Australia) about to start

[Seymour J Metz]

Not every paradigm has a name, and not every use of a name has the same 
definition. When I'm using a specific language I use the nomenclature for that 
language; in a more general context, all bets are off.

You have a similar situation in Mathematics, where texts typically start with 
the nomenclature and conventions used, but even within a text there may be 
chapters with a different convention.

--
Shmuel (Seymour J.) Metz
http://mason.gmu.edu/~smetz3
עַם יִשְׂרָאֵל חַי
נֵ֣צַח יִשְׂרָאֵ֔ל לֹ֥א יְשַׁקֵּ֖ר


From: IBM Mainframe Discussion List  on behalf of Bob 
Bridges <0587168ababf-dmarc-requ...@listserv.ua.edu>
Sent: Monday, March 4, 2024 5:24 PM
To: IBM-MAIN@LISTSERV.UA.EDU
Subject: Re: 35th International Rexx Symposium in Birsbane (Australia) about to 
start

Well, let me focus on that one thing.  If I can define a class as a cluster of 
data values and/or subroutines, and instantiate objects in that class, then 
isn't that "object-oriented" even if it doesn't have any features to define 
inheritance from other classes?  You may think it's a pretty feature-poor 
example of it, but what else would you call it if not "object-oriented"?

---
Bob Bridges, robhbrid...@gmail.com, cell 336 382-7313

/* In order to write for "The A-Team", you'd have to be a much better writer 
than most of those who write the evening news at networks and local stations — 
forget about shows like "Hill Street Blues" or "The Muppet Show", where writing 
REALLY counts.  -Linda Ellerbee in _And So It Goes_ */

-Original Message-
From: IBM Mainframe Discussion List  On Behalf Of 
Seymour J Metz
Sent: Monday, March 4, 2024 15:19

I'ld say that to be  OO it must at least have inheritance.


From: Bob Bridges
Sent: Monday, March 4, 2024 2:30 PM

Well, yeah.  But a) I'm not far enough into that debate to understand all the 
issues and distinctions, and b) at any rate "object-oriented" means SOMETHING.  
As I said, when he wrote "dynamic" I was sure he didn't mean just "lively" or 
"ever-changing".

Heck, I'm satisfied if "object-oriented" means merely that I can define objects 
and create instances of them.  All the other stuff about inheritance and other 
even more arcane features, they're great, but I wouldn't say a language cannot 
be object-oriented without them.

-Original Message-
From: IBM Mainframe Discussion List  On Behalf Of 
Seymour J Metz
Sent: Sunday, March 3, 2024 00:33

Actually, there's been a decades long language war over what object-oriented 
means.

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Re: TELNET PROFILE, strictly PDS?

[roscoe5]

Thanks for all the comments from everyone. They were useful, relevant, and 
confirmed what I guessed.
I built a new PDS/E Library and planned to pick it up as each LPAR was IPLed.
In the end, the Compress while in use was enough. The free space should last 
until after I retire, again.
This group is great!
Thanks again,
Out.

Sent from [Proton Mail](https://proton.me/mail/home) for iOS

On Tue, Mar 5, 2024 at 12:49 PM, Radoslaw Skorupka 
<[0471ebeac275-dmarc-requ...@listserv.ua.edu](mailto:On Tue, Mar 5, 2024 at 
12:49 PM, Radoslaw Skorupka < wrote:

> W dniu 04.03.2024 o 20:29, Wendell Lovewell pisze:
>> As Allan said, you can compress an in-use PDS using IEBCOPY.
>>
>> //CMP EXEC PGM=IEBCOPY
>> //SYSPRINT DD SYSOUT=*
>> //SYSUT3 DD UNIT=SYSDA,SPACE=(CYL,(90))
>> //SYSUT4 DD UNIT=SYSDA,SPACE=(CYL,(90))
>> //INDD0 DD DISP=SHR,DSN=&YOURPDS
>> //SYSIN DD *
>> C I=INDD0,O=INDD0
>> /*
>>
>> You might have to adjust the SYSUT3/4 space.
>
> My advice: use contemporary REGION and get rid of both SYSUT3/4 ddnames.
> Especially for small datasets like TCPPARM.
>
> --
> Radoslaw Skorupka
> Lodz, Poland
>
> --
> For IBM-MAIN subscribe / signoff / archive access instructions,
> send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN

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Re: How to reduce the overhead of WLM?

[Allan Staller]

Classification: Confidential

The most important resource in most shops is CPU and is usually the critical 
factor in WLM adjustments.
Judicious user of SC period and IMPortance is far more effective in controlling 
the distribution of CPU.
.
I would not overload SYSSTC with work, this will prevent WLM from servicing 
really critical stuff (GRS, XCF, IRLM,..).
However it’s not my dog.

Another thought to the OP. Are you trying to reduce overhead because of a CPU 
shortage, or just curious? Think absolute value vs percentage.
In Sandbox environments, very often something like WLM appears to be the 
largest consumer of CPU), but in absolute terms it is really minor.

HTH,


-Original Message-
From: IBM Mainframe Discussion List  On Behalf Of Tom 
Marchant
Sent: Tuesday, March 5, 2024 7:59 AM
To: IBM-MAIN@LISTSERV.UA.EDU
Subject: Re: How to reduce the overhead of WLM?

[CAUTION: This Email is from outside the Organization. Unless you trust the 
sender, Don’t click links or open attachments as it may be a Phishing email, 
which can steal your Information and compromise your Computer.]

Would it help to have more of those address spaces in SYSSTC so that WLM 
doesn't try to manage them?

--
Tom Marchant

On Tue, 5 Mar 2024 01:03:27 +, Graham Harris  wrote:

>A few years back, I did a deep dive into tuning CPU usage across a
>multitude of very small z/OS guests under z/VM, and WLM was certainly a
>big hitter for many of them, but as there were so many instances, I was
>able to see notable differences in WLM use between "LPARs", which was
>obviously "of interest".
>The upshot seemed to be that WLM costs had a fairly firm relationship
>with the number of active address spaces on the "LPAR", presumably down
>to the amount of sampling that WLM has to do against each address space
>every 250ms (I think).  I did enquire of IBM as to whether the sampling
>rate could be "adjusted", and that came back with a negative response
>(not really a surprise).
>So the obvious answer may be to only have address spaces started, when
>they are only really needed to be there.
>Although you may need to assess the cost of stopping/starting those
>address spaces, versus the background WLM cost.
>
>
>On Mon, 4 Mar 2024 at 23:08, Wendell Lovewell <
>01e9c0ee0673-dmarc-requ...@listserv.ua.edu> wrote:
>
>> This is probably a strange question, but is there a way to reduce WLM cpu
>> usage?   Here's the situation:
>>
>> - The system is a lightly used development system.  Unless something
>> is in a loop (very rare), CPU % probably is usually less than 10%.
>> And except for system regions & CICS, it's rare to have multiple jobs
>> running concurrently.
>> - Only one processor defined to the VM. No ZIIP either.
>> - We are charged for CPU cycles.
>> - WLM is the highest consumer of CPU.  JES2, TCPIP, ZFS and SDSFAUX
>> round out the top 5 consumers.
>>
>> There is a lot of information about WLM tuning, but as best I can
>> tell almost none of it relates to reducing WLM usage.
>>
>> From reading the Init & Tuning manual, I'm trying these settings:
>> AIMANAGEMENT=NO
>> HIPERDISPATCH=NO
>> CCCAWMT=45
>> RMPTTOM=15000
>>
>> I was thinking that perhaps reducing whatever processing intervals I
>> could might help.  But I can't tell these changes made a difference.
>> (I don't have a tool to measure WLM usage.)
>>
>> Any suggestions would be appreciated.
>>
>> TIA,
>>
>> Wendell
>>
>> -
>> - For IBM-MAIN subscribe / signoff / archive access instructions,
>> send email to lists...@listserv.ua.edu with the message: INFO
>> IBM-MAIN
>>
>
>--
>For IBM-MAIN subscribe / signoff / archive access instructions, send
>email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN

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The contents of this e-mail and any attachment(s) are confidential and intended 
for the named recipient(s) only. E-mail transmission is not guaranteed to be 
secure or error-free as information could be intercepted, corrupted, lost, 
destroyed, arrive late or incomplete, or may contain viruses in transmission. 
The e mail and its contents (with or without referred errors) shall therefore 
not attach any liability on the originator or HCL or its affiliates. Views or 
opinions, if any, presented in this email are solely those of the author and 
may not necessarily reflect the views or opinions of HCL or its affiliates. Any 
form of reproduction, dissemination, copying, disclosure, modification, 
distribution and / or publication of this message without the prior written 
consent of authorized representative of HCL is strictly prohibited. If you have 
received this email in erro

Re: How to reduce the overhead of WLM?

[Farley, Peter]

In this case the OP stated that they are PAYING for CPU cycles on a mostly idle 
machine, so to me the implication is that they wish to reduce their CPU cost by 
reducing idle CPU cycles.

From: IBM Mainframe Discussion List  On Behalf Of 
Allan Staller
Sent: Tuesday, March 5, 2024 1:23 PM
To: IBM-MAIN@LISTSERV.UA.EDU
Subject: Re: How to reduce the overhead of WLM?


Classification: Confidential



The most important resource in most shops is CPU and is usually the critical 
factor in WLM adjustments.

Judicious user of SC period and IMPortance is far more effective in controlling 
the distribution of CPU.

.

I would not overload SYSSTC with work, this will prevent WLM from servicing 
really critical stuff (GRS, XCF, IRLM,..).

However it’s not my dog.



Another thought to the OP. Are you trying to reduce overhead because of a CPU 
shortage, or just curious? Think absolute value vs percentage.

In Sandbox environments, very often something like WLM appears to be the 
largest consumer of CPU), but in absolute terms it is really minor.



HTH,





-Original Message-

From: IBM Mainframe Discussion List 
mailto:IBM-MAIN@LISTSERV.UA.EDU>> On Behalf Of Tom 
Marchant

Sent: Tuesday, March 5, 2024 7:59 AM

To: IBM-MAIN@LISTSERV.UA.EDU

Subject: Re: How to reduce the overhead of WLM?



[CAUTION: This Email is from outside the Organization. Unless you trust the 
sender, Don’t click links or open attachments as it may be a Phishing email, 
which can steal your Information and compromise your Computer.]



Would it help to have more of those address spaces in SYSSTC so that WLM 
doesn't try to manage them?



--

Tom Marchant



On Tue, 5 Mar 2024 01:03:27 +, Graham Harris 
mailto:harris...@gmail.com>> wrote:



>A few years back, I did a deep dive into tuning CPU usage across a

>multitude of very small z/OS guests under z/VM, and WLM was certainly a

>big hitter for many of them, but as there were so many instances, I was

>able to see notable differences in WLM use between "LPARs", which was

>obviously "of interest".

>The upshot seemed to be that WLM costs had a fairly firm relationship

>with the number of active address spaces on the "LPAR", presumably down

>to the amount of sampling that WLM has to do against each address space

>every 250ms (I think).  I did enquire of IBM as to whether the sampling

>rate could be "adjusted", and that came back with a negative response

>(not really a surprise).

>So the obvious answer may be to only have address spaces started, when

>they are only really needed to be there.

>Although you may need to assess the cost of stopping/starting those

>address spaces, versus the background WLM cost.

>

>

>On Mon, 4 Mar 2024 at 23:08, Wendell Lovewell <

>01e9c0ee0673-dmarc-requ...@listserv.ua.edu>
> wrote:

>

>> This is probably a strange question, but is there a way to reduce WLM cpu

>> usage?   Here's the situation:

>>

>> - The system is a lightly used development system.  Unless something

>> is in a loop (very rare), CPU % probably is usually less than 10%.

>> And except for system regions & CICS, it's rare to have multiple jobs

>> running concurrently.

>> - Only one processor defined to the VM. No ZIIP either.

>> - We are charged for CPU cycles.

>> - WLM is the highest consumer of CPU.  JES2, TCPIP, ZFS and SDSFAUX

>> round out the top 5 consumers.

>>

>> There is a lot of information about WLM tuning, but as best I can

>> tell almost none of it relates to reducing WLM usage.

>>

>> From reading the Init & Tuning manual, I'm trying these settings:

>> AIMANAGEMENT=NO

>> HIPERDISPATCH=NO

>> CCCAWMT=45

>> RMPTTOM=15000

>>

>> I was thinking that perhaps reducing whatever processing intervals I

>> could might help.  But I can't tell these changes made a difference.

>> (I don't have a tool to measure WLM usage.)

>>

>> Any suggestions would be appreciated.

>>

>> TIA,

>>

>> Wendell

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Re: EXTERNAL EMAIL: Re: How to reduce the overhead of WLM?

[Jerry Whitteridge]

During the hullabaloo of the Y2K testing period I had a dedicated CEC for Y2K 
testing so we could change the dates as necessary. I ran that box for a 
considerable time using SYSTEM, SYSSTC and everything else got placed in 
Discretionary. This worked just fine for a development/testing environment. 
This MIGHT help the OP

Jerry Whitteridge
Sr Manager Managed Services
jerry.whitteri...@albertsons.com
480 578 7889

-Original Message-
From: IBM Mainframe Discussion List  On Behalf Of 
Allan Staller
Sent: Tuesday, March 5, 2024 11:23 AM
To: IBM-MAIN@LISTSERV.UA.EDU
Subject: EXTERNAL EMAIL: Re: How to reduce the overhead of WLM?

Classification: Confidential

The most important resource in most shops is CPU and is usually the critical 
factor in WLM adjustments.
Judicious user of SC period and IMPortance is far more effective in controlling 
the distribution of CPU.
.
I would not overload SYSSTC with work, this will prevent WLM from servicing 
really critical stuff (GRS, XCF, IRLM,..).
However it’s not my dog.

Another thought to the OP. Are you trying to reduce overhead because of a CPU 
shortage, or just curious? Think absolute value vs percentage.
In Sandbox environments, very often something like WLM appears to be the 
largest consumer of CPU), but in absolute terms it is really minor.

HTH,


-Original Message-
From: IBM Mainframe Discussion List  On Behalf Of Tom 
Marchant
Sent: Tuesday, March 5, 2024 7:59 AM
To: IBM-MAIN@LISTSERV.UA.EDU
Subject: Re: How to reduce the overhead of WLM?

[CAUTION: This Email is from outside the Organization. Unless you trust the 
sender, Don’t click links or open attachments as it may be a Phishing email, 
which can steal your Information and compromise your Computer.]

Would it help to have more of those address spaces in SYSSTC so that WLM 
doesn't try to manage them?

--
Tom Marchant

On Tue, 5 Mar 2024 01:03:27 +, Graham Harris  wrote:

>A few years back, I did a deep dive into tuning CPU usage across a
>multitude of very small z/OS guests under z/VM, and WLM was certainly a
>big hitter for many of them, but as there were so many instances, I was
>able to see notable differences in WLM use between "LPARs", which was
>obviously "of interest".
>The upshot seemed to be that WLM costs had a fairly firm relationship
>with the number of active address spaces on the "LPAR", presumably down
>to the amount of sampling that WLM has to do against each address space
>every 250ms (I think).  I did enquire of IBM as to whether the sampling
>rate could be "adjusted", and that came back with a negative response
>(not really a surprise).
>So the obvious answer may be to only have address spaces started, when
>they are only really needed to be there.
>Although you may need to assess the cost of stopping/starting those
>address spaces, versus the background WLM cost.
>
>
>On Mon, 4 Mar 2024 at 23:08, Wendell Lovewell <
>01e9c0ee0673-dmarc-requ...@listserv.ua.edu> wrote:
>
>> This is probably a strange question, but is there a way to reduce WLM cpu
>> usage?   Here's the situation:
>>
>> - The system is a lightly used development system.  Unless something
>> is in a loop (very rare), CPU % probably is usually less than 10%.
>> And except for system regions & CICS, it's rare to have multiple jobs
>> running concurrently.
>> - Only one processor defined to the VM. No ZIIP either.
>> - We are charged for CPU cycles.
>> - WLM is the highest consumer of CPU.  JES2, TCPIP, ZFS and SDSFAUX
>> round out the top 5 consumers.
>>
>> There is a lot of information about WLM tuning, but as best I can
>> tell almost none of it relates to reducing WLM usage.
>>
>> From reading the Init & Tuning manual, I'm trying these settings:
>> AIMANAGEMENT=NO
>> HIPERDISPATCH=NO
>> CCCAWMT=45
>> RMPTTOM=15000
>>
>> I was thinking that perhaps reducing whatever processing intervals I
>> could might help.  But I can't tell these changes made a difference.
>> (I don't have a tool to measure WLM usage.)
>>
>> Any suggestions would be appreciated.
>>
>> TIA,
>>
>> Wendell
>>
>> -
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>>
>
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Re: How to reduce the overhead of WLM?

[Wendell Lovewell]

Thanks for your advice everyone.

Graham:  The 250ms interval seems to me to be the crux of the problem.  I was 
hoping for a way to adjust it.  We don't have all that many "user work" address 
spaces started.  Usually only one CICS region.

Jim: I've set RMPTTOM to 45000.  Going from 3000 to 15000 didn't seem to have 
an effect, but I was hesitant at shooting too high. 

Allan: We have little to no usage of those subsystems--even CICS is pretty 
lightly used. My goal is to reduce the CPU usage in the WLM & other system 
address spaces because we pay for CPU cycles.

Peter: That's correct.

Wendell

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IBM Announces the z/OS Container Platform

[Timothy Sipples]

I’d like to draw your attention to this IBM announcement:

https://www.ibm.com/docs/en/announcements/zos-container-platform-delivers-industry-standard-cloud-technologies-build-run-zos-unix-applications-as-containers-natively-zos

—
Timothy Sipples
Senior Architect
Digital Assets, Industry Solutions, and Cybersecurity
IBM Z/LinuxONE, Asia-Pacific
sipp...@sg.ibm.com


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Re: ZOS Sending Logs to Sumologic Experience?

[kekronbekron]

I don't understand this at all... we all know that SMF is not a log, it's a 
whole bunch of strings & mostly numbers... metrics.
Why has it become acceptable to send metrics to a log search tool, knowing full 
well that these are different categories with different solutions.
Splunk etc. are meant to collect and search through things like http web server 
log, not metrics.
The information density in a log is low. In SMF, it's very high (there are no 
fluff words, just metrics which may or may not be of use during a given 
activity).



On Tuesday, March 5th, 2024 at 00:13, Steve Estle 
<05dcac13570d-dmarc-requ...@listserv.ua.edu> wrote:

> All,
> 
> We are embarking on an endeavor to explore sending logics to a tool called 
> Sumologic(sumologic.com). For those who are unaware, Sumologic is a 
> competitor to Splunk and contains a very powerful real time log parsing 
> analytics engine which can be used to build dashboards, alerts, and more. My 
> basic question is has anyone heard of or actually been involved in devising 
> ways to send ZOS logs into Sumalogic - our initial efforts will be security 
> related, but for now am just asking if anyone has any experience in this 
> realm at all? Or maybe you are doing something similar to Splunk? If so, you 
> can post in forum or feel free to reach directly out to me:
> 
> Thanks much,
> 
> Steve Estle
> sest...@gmail.com
> 303-817-9954
> 
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WLM - service class and Dispatch priority

[Peter]

Hello

I must confess that I am not a WLM expert but I just wanted to understand
how this works

In our environment we have few started where their Service class(Velocity)
and Dispatch priority keeps changing on its own.

Based on what constraint or definition in WLM the service class and
Dispatch priority are dynamic? Keeping a static value would be right thing
to do ?
Sometimes those task loop and freezes the entire zOS. So If I make those
started task Service class and DP static then will it help consuming the
zOS memory due to looping?

Sorry if this question are basic and lacks some information

Any suggestions or advice are much appreciated

Peter

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BASE64 Decode / EPOCH Conversion Code Samples

[Frank Bonaduce]

Hello Folks. Is anyone aware of where one might locate any sample assembler 
code, macros or APIs to perform the following:
- Base64 Decoding (to EBCDIC)- EPOCH Conversion
Thanks in advance for the assistance.   Frank.

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Re: BASE64 Decode / EPOCH Conversion Code Samples

[Binyamin Dissen]

Base64 has nothing to do with EBCDIC.

It is a means of converting binary data to commonly printable characters
(typically A-Z a-z 0-9 + /)  that can then be shipped in a non-binary manner.

A simple duck-duck-go search will show examples. My first C program was a base
64 converter.

On Wed, 6 Mar 2024 06:11:01 + Frank Bonaduce
<05e50174f43c-dmarc-requ...@listserv.ua.edu> wrote:

:>Hello Folks. Is anyone aware of where one might locate any sample assembler 
code, macros or APIs to perform the following:
:>- Base64 Decoding (to EBCDIC)- EPOCH Conversion
:>Thanks in advance for the assistance.   Frank.

--
Binyamin Dissen 
http://www.dissensoftware.com

Director, Dissen Software, Bar & Grill - Israel

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