©Copyright 2004, Computer Management Sciences, Inc., Alexandria, VA 1 Introduction to zAAP (zSeries Application Assist Processor) Don

©Copyright 2004, Computer Management Sciences, Inc., Alexandria, VA www.cpexpert.com 1

Introduction to zAAP(zSeries Application Assist Processor)

Don Deese

Computer Management Sciences, Inc.www.cpexpert.com

All trademarks are the property of their respective owners.


Presentation Outline

Overview of zAAP (IFA) Processor

Benefits and requirements of zAAP

Description of how zAAP works

User controls for zAAP processing

Performance considerations with zAAP

Data available to measure zAAP performance

Conclusions and references

NOTE: zAAP operates only in a PR/SM environment. All references to “central processor” or “zAAP/IFA processor” should be taken to mean “logical central processor” and “logical zAAP/IFA processor”.


What is zAAP (IFA) Processor

“Special processor” available with z890, z990, z9.

Called either zAAP or IFA (Integrated Facility for Applications) depending on IBM document.

Runs only JAVA work (zAAP-eligible work) under control of JVM.

Similar to IFL (Integrated Facility for Linux).

Does not increase MSU rating of z890, z990, or z9.

Purchase and maintenance cost are significantly lower than with standard central processor.


PU SAP SAPPU PU PU PU PU PU PU

Central processors (CP)

CP CP CP CP

Special processors

ICF IFL IFA

Z990 Processor Units – sample definition

spare spare

Internal Coupling FacilityICF

IFL Integrated Facility for Linux

IFA Integrated Facility for Applications

PU Unused

SAP System Assist Processor

Special processors


PU SAPPU PU PU


CP CP

Z890 Processor Units – sample definition

IFA Integrated Facility for Applications

SAP System Assist Processor

Special processors

z890 #CP #IFA61nn 1 1

62nn 2 2

63nn 3 1

64nn 4 0

IFAIFA


Benefits of zAAP Processors

Attractively priced ($125K USD per zAAP engine).

IBM zSeries software charges are unaffected (MSU rating is unchanged when zAAP is added).

Can run JAVA work on zAAP attached to z890 (zAAP runs at full speed, while z890 CPs can run at potentially much lower sub-capacity speed).

Sub-capacity IBM software charges could be reduced.

Significantly lower maintenance costs than standard CPs.

Up to one zAAP processor per central processor in a CPC.


Limitations of zAAP processors

Available only with z890 and z990 (and above)

Only one zAAP per purchased central processor

Cannot execute user instructions (other than under control of JVM)

Does not processes I/O interrupts

With z890/z990, zAAP inherits LPAR attributes from LPAR definition

Does not participate in IRD management and retains initial LPAR weight even if WLM changes LPAR weight

Does not support WLM soft-capping (meaningless since IFA is not reflected in defined capacity)


How does zAAP (IFA) work?

zAAP-eligible work must be processed in LPAR with one or more normal CPs

JVM decides whether JAVA work is zAAP-eligible.

JVM notifies z/OS dispatcher that zAAP-eligible work is ready to execute

zAAP-eligible work is dispatched to IFA (or to CP).

User specifications control whether zAAP-eligible work executes on IFA and on CP, or executes only on IFA.

User specifications control whether zAAP-eligible work executes in competition with normal “goal” work.


Example flow when JAVA work is executed on IFA


zAAP External Controls in IEAOPTxx

IFACROSSOVER

IFAHONORPRIORITY

With z/OS V1R6, specifies whether zAAP-eligible work can “cross over” to run on CP as well as on IFA.

Meaning and importance changes with z/OS V1R7.

Specifies whether zAAP-eligible work and other work will be dispatched to both CP and IFA based on WLM-

assigned priority.

zAAP-eligible work will always be dispatched on IFAbased on WLM-assigned priority.

If zAAP-eligible work runs on CP below DISC priority, zAAP-eligible work will be dispatched based on WLM-

assigned priority for the zAAP-eligible work.


X-OVER HON-PRI Meaning

YES YES Dispatch zAAP-eligible work to both CP and IFA, in dispatching priority order. Soft-capping in effect dispatch at priority below discretionary.

YES NO Dispatch zAAP-eligible work to IFA and dispatch to CP below discretionary.

NO N/A Dispatch zAAP-eligible work only to IFA. If no available IFA dispatch to CP at priority below discretionary.

zAAP Controls with z/OS V1R6IFACROSSOVER and IFAHONORPRIORITY

But see OA14131 (applies z/OS V1R7 changes)


zAAP Controls with z/OS V1R7IFAHONORPRIORITY, AWM, and IFACROSSOVER

HON-PRI AWM X-OVER MeaningYES YES N/A Dispatch zAAP-eligible work to both CP

and IFA, in dispatching priority order. Soft-capping in effect dispatch to CP at priority below DISC. But see OA13953!

YES NO YES Dispatch zAAP-eligible work to IFA and dispatch to CP below DISC.

YES NO NO Run zAAP-eligible work on CP only if no IFA in LPAR.

NO N/A YES Dispatch zAAP-eligible work to IFA and dispatch to CP below DISC.

NO N/A NO Run zAAP-eligible work on CP only if no IFA in LPAR.

AWM = Alternate Wait State Management


WORK UNIT PRIORITY

Goal, not zAAP #5 243



DISCR, not zAAP #1 192

WORK UNIT PRIORITY

zAAP-eligible #4 249




SYSTEM DISPATCH QUEUE IFA DISPATCH QUEUE

Sample z/OS DispatchingIFACROSSOVER=YES (with z/OS V1R6)

AWM decides IFA “needs help” (with z/OS V1R7)IFAHONORPRIORITY=YES

z/OS Dispatcher selects “zAAP-eligible #4” for dispatch, since it is the highest priority.

If IFA available, dispatch to IFA.

If IFA not available, dispatch to CP.


WORK UNIT PRIORITY





WORK UNIT PRIORITY






Sample z/OS DispatchingIFACROSSOVER=YES

IFAHONORPRIORITY=NO

If IFA available, z/OS Dispatcher selects “zAAP-eligible #4”for dispatch, since it is highest priority.

z/OS Dispatcher selects “zAAP-eligible #4” for dispatch on CP below DISC.

.


WORK UNIT PRIORITY





WORK UNIT PRIORITY






Sample z/OS DispatchingIFACROSSOVER=NO

IFAHONORPRIORITY=NO

If IFA available, z/OS Dispatcher selects “zAAP-eligible #4”for dispatch, since it is highest priority.

z/OS Dispatcher will select “zAAP-eligible #4” for dispatch on CP only if no IFA in LPAR.


zAAP Performance considerationsz/OS V1R6 and z890/z990

Large number of central processors versus zAAP processors defined to LPAR

High Goal Importance of zAAP-eligible work

Low Goal Importance of zAAP-eligible work

High CPU activity level of central processors

With z890/z990, LPAR definitions could conflict with

LPAR definitions for other shared special processors

in “Pool 2”. Problem solved with z9 109.

PR/SM Logical to Physical processor ratio


WORK UNIT PRIORITY





WORK UNIT PRIORITY






Performance consideration with zAAP, z/OS V1R6IFACROSSOVER=YES

IFAHONORPRIORITY=YES

z/OS Dispatcher selects “zAAP-eligible #4” for dispatch. If IFA available, dispatch to IFA. If IFA not available, dispatch to CP.

With large number of logical CPs, zAAP-eligible work will tend to be done by CPs, rather than by IFA.


WORK UNIT PRIORITY





WORK UNIT PRIORITY









With high Goal Importance, zAAP-eligible work will tend to be done by CPs, rather than by IFA.


WORK UNIT PRIORITY





WORK UNIT PRIORITY









With low Goal Importance, zAAP-eligible work will tend to be done only by IFAs, which could imply that

more zAAP processors are needed than expected.


WORK UNIT PRIORITY





WORK UNIT PRIORITY






Performance consideration with zAAP, z/OS V1R6IFACROSSOVER=NO

IFAHONORPRIORITY=not applicable

If IFA available, z/OS Dispatcher on IFA selects “zAAP-eligible #4”for dispatch.z/OS Dispatcher on CP selects “zAAP-eligible #4” for

dispatch only after “DISCR, not zAAP #1” dispatched.

If small number of IFAs defined to LPAR, zAAP-eligible work will tend to be delayed waiting on IFA.


LPAR WEIGHT SHARE LCP IFA

SYSA 50 5.0% 1 0

SYSB 200 20.0% 2 0

SYSC 200 20.0% 2 0

SYSD 400 40.0% 3 0

SYSE 150 15.0% 2 1

TOTAL 1000 100.0% 10LPAR WEIGHT SHARE LSP %SP

LINUX1 10 5.9% 1 11.8%

LINUX2 10 5.9% 1 11.8%

SYSE 150 88.2% 1 176.5%

TOTAL 170 100.0% 200.0%

LPAR WEIGHT SHARE LSP %SP

LINUX1 10 50.0% 1 50.0%

LINUX2 10 50.0% 1 50.0%

TOTAL 20 100.0% 100.0%


CP CP CP CP

Special processors (SP)

ICF IFL IFA

Before IFA

After IFA (Example only. SYSE cannot really have over 100% as only 1 IFA assigned to SYSE.)

Dedicated

Performance consideration with zAAP on z890/z990LPAR Definitions

LCP = Logical Central ProcessorLSP = Logical Special Processor



CP CP CP CP


ICF IFL IFA

Dedicated


LINUX1 75 25.0% 1 50%

LINUX2 75 25.0% 1 50%

SYSE 150 50.0% 1 100%

TOTAL 300 100.0% 200%


SYSA 50 5.0% 1 0

SYSB 200 20.0% 2 0

SYSC 200 20.0% 2 0

SYSD 400 40.0% 3 0

SYSE 150 15.0% 2 1

TOTAL 1000 100.0% 10

This situation really is no different than when adding any LPAR (except the zAAPpart is inherited from the central processor LPAR definition). You must carefullyreview your weights and resulting shares considering LPARs with zAAPs.




CP CP CP CP


ICF IFL IFA

Dedicated


LINUX1 75 6.5% 1 19.6%

LINUX2 75 6.5% 1 19.6%

SYSA 50 4.3% 2 13.0%

SYSB 200 17.4% 2 26.1%

SYSC 200 17.4% 2 52.2%

SYSD 400 34.8% 2 52.2%

SYSE 150 13.0% 2 39.1%

TOTAL 1150 100.0% 12


SYSA 50 5.0% 1 2

SYSB 200 20.0% 2 2

SYSC 200 20.0% 2 2

SYSD 400 40.0% 3 2

SYSE 150 15.0% 2 2

TOTAL 1000 100.0% 10 10

IFA




CP CP CP CP


ICF IFL IFA

Dedicated


LINUX1 250 16.7% 1 50.0%

LINUX2 250 16.7% 1 50.0%

SYSA 50 3.3% 2 5.0%

SYSB 200 13.3% 2 20.0%

SYSC 200 13.3% 2 40.0%

SYSD 400 26.7% 2 40.0%

SYSE 150 10.0% 2 15.0%

TOTAL 1500 100.0% 12


SYSA 50 5.0% 1 2

SYSB 200 20.0% 2 2

SYSC 200 20.0% 2 2

SYSD 400 40.0% 3 2

SYSE 150 15.0% 2 2

TOTAL 1000 100.0% 10 10

IFA

• Logical to Physical ratio - 12:3 (4:1)• IFL & IFA share comes from same pool• Unused IFL capacity can be used for IFA



RMF zAAP performance data

TYPE 72 DescriptionR723IFAU Samples of zAAP-eligible work using a processor.

R723IFCU Samples of zAAP-eligible work executing on a CP.

R723IFAD Samples of zAAP-eligible work that was delayed, waiting for a processor.

R723IFAT IFA processor time used by zAAP-eligible work.

R723NFFI Normalization factor for CP versus IFA speed.

R723MFLG Indicators of IFACROSSOVER and IFAHONORPRIORITY specification.

R723IFCT IFA processor time spent on normal CPs.


Conclusions zAAP offering appears to be an excellent way to obtain

significantly increased processor capacity at a very attractive price.

Sufficient zAAP-eligible work must exist.

PR/SM definitions must be carefully reviewed (most problems solved with z9 109).

Service class Performance Goals and Goal Importance must be carefully considered.

IBM has provided sufficient RMF data for analysts to determine IFA processor capacity requirements and performance

problems.

OW14131 and OW13953 solve many problems with z/OS V1R6.


References GM13-0624 – Introducing the new zSeries Application Assist Processor

SG24-6310: IBM zSeries 890 Technical Introduction

SG24-6947: IBM zSeries 990 Technical Guide

SG24-6669: IBM z9 109 Technical Introduction

SG24-6386: zSeries Application Assist Processor (zAAP) Implementation

SB10-7036-03: zSeries 890 and 990 Processor Resource/Systems Manager Planning Guide

SG24-5922: z/OS Intelligent Resource Director

z/OS MVS Planning: Workload Management (z/OS V1R6 and z/OS V1R7)

MVS Initialization and Tuning Reference (z/OS V1R6 and z/OS V1R7)

z/OS Performance: Capacity Planning Considerations for zAAP White Paper

z990 and z890 zAAP - What it Can Do for You SHARE - Summer, 2004 MVS SCP Project Session: 2825, Kathy Walsh (IBM Washington Systems Center, Advanced Technical Support)


References IBM White Paper (WP100489) Mission: zAAP your costs, Running Websphere

and Java on the zSeries Application Assist Processor (updated)

IBM White Paper (WP100417) z/OS Performance: Capacity PlanningConsiderations for zAAP Processors

IBM EXPO 2005, Session P06 z/OS Performance "HOT" Topics, Kathy Walsh (IBM Washington Systems Center, Advanced Technical Support)

IBM EXPO 2005, Session P25 Everything zAAP, Kathy Walsh (IBM Washington Systems Center, Advanced Technical Support)

APAR 0A14131 and APAR 0A13953

http://www-1.ibm.com/servers/eserver/zseries/zaap/gettingstarted/


Introduction to zAAP(zSeries Application Assist Processor)

Don Deese

Computer Management Sciences, Inc.www.cpexpert.com

All trademarks are the property of their respective owners.


4-WAY MSU

410 15

420 26

430 49

440 62

450 97

460 119

470 208

1-WAY MSU

110 4

120 7

130 13

140 17

150 26

160 32

170 56

z890 Sub-capacity MSU rating(28 capacity levels)

zAAP processor runs at full speedRegardless of capacity rating!

Documents

©Copyright 2004, Computer Management Sciences, Inc., Alexandria, VA 1 Introduction to zAAP (zSeries Application Assist Processor) Don