PI92171: AN INTERMITTENT PERFORMANCE DEGRADATION IS OBSERVED WITH CICS V5.4 AND LIBERTY 17.0.0.3 COMPARED TO LIBERTY 17.0.0.1

Fixes are available

APAR status

Closed as program error.

Error description

An intermittent performance degradation has been observed
running with CICS V5.4 with Liberty 17.0.0.3
compared to CICS V5.4 with Liberty 17.0.0.1.
Possibly  due to a change in processing incoming socket
requests.

One instance was about 4% increase in CPU cost per servlet
request with sampling data. The sampling data showed that
17.0.0.3 used of some functions not evident in 17.0.0.1
related
to TCP Select Pool.  These functions were EZBTCFSP(TCP/IP
Select Poll) in the TCPIP region and  BPXTCSEL and EZBPFSEL
(TCP/IP PFS Select) in OMVS region.

Taking Javacore dumps of 17.0.0.1 and 17.0.0.3 running the
same
workload may show there is a difference in the threads.
17.0.0.3 as an "Inbound Read Selector.1" that uses quite a
lot
of CPU 'CPU usage total: 85.861000000 secs'.  17.0.0.1 has a
different thread structure.

Local fix

```
n/a
```

Problem summary

****************************************************************
* USERS AFFECTED:  Users of IBM WebSphere Application Server   *
*                  Liberty running inside a CICS TS V5.4       *
*                  environment on z/OS.                        *
****************************************************************
* PROBLEM DESCRIPTION: I/O performance degradation when        *
*                      running Liberty inside a CICS TS V5.4   *
*                      environment.                            *
****************************************************************
* RECOMMENDATION:                                              *
****************************************************************
WebSphere Application Server Liberty for z/OS has a z/OS-
specific I/O performance enhancement that is supposed to be
enabled by default when running anywhere on the z/OS platform,
including when running inside a CICS TS V5.4 environment.

However, a specific configuration setting of the CICS TS V5.4
environment accidentally disables this enhancement, leading to a
performance degradation.

Problem conclusion

Updated the code so that the z/OS-specific I/O performance
enhancement is enabled when running WebSphere Liberty inside a
CICS TS V5.4 environment.

The fix for this APAR is currently targeted for inclusion in fix
pack 18.0.0.1.  Please refer to the Recommended Updates page for
delivery information:
http://www.ibm.com/support/docview.wss?rs=180&uid=swg27004980

Temporary fix

Comments

APAR Information

APAR number
PI92171
Reported component name
LIBERTY PROF -
Reported component ID
5655W6514
Reported release
CD0
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2018-01-09
Closed date
2018-01-31
Last modified date
2018-01-31

APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:

Fix information

Fixed component name
LIBERTY PROF -
Fixed component ID
5655W6514

Applicable component levels

RCD0 PSY
UP

[{"Business Unit":{"code":"BU059","label":"IBM Software w\/o TPS"},"Product":{"code":"SS7K4U","label":"WebSphere Application Server for z\/OS"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"CD0","Line of Business":{"code":"LOB45","label":"Automation"}}]

Document Information

Modified date:
04 May 2022

Tips

PI92171: AN INTERMITTENT PERFORMANCE DEGRADATION IS OBSERVED WITH CICS V5.4 AND LIBERTY 17.0.0.3 COMPARED TO LIBERTY 17.0.0.1

Fixes are available

Subscribe

APAR status

Closed as program error.

Error description

Local fix

Problem summary

Problem conclusion

Temporary fix

Comments

APAR Information

APAR number

Reported component name

Reported component ID

Reported release

Status

PE

HIPER

Special Attention

Submitted date

Closed date

Last modified date

APAR is sysrouted FROM one or more of the following:

APAR is sysrouted TO one or more of the following:

Fix information

Fixed component name

Fixed component ID

Applicable component levels

RCD0 PSY

Document Information

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