IBM Advanced Technical Support

z/OS Performance "Hot" Topics

Kathy WalshIBM CorporationIBM Distinguished EngineerWashington Systems Center

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Trademarks and Disclaimers

HiperSocketsIBM* IBM eServerIBM logo*iSeriesLotus*OnForever*Parallel Sysplex*POWERPOWER5Predictive Failure Analysis*pSeries*

S/390ServerProven*Tivoli*TotalStorage*TotalStorage ProvenVirtualization EngineX-ArchitecturexSeries*z/OS*z/VM*zSeries*System z9*

AIX*AIX 5L*BladeCenterChipkillDB2DB2 Universal DatabaseDominoEnterprise Storage Server*e-business logo*GDPS*Geographically Dispersed Parallel Sysplex

* Registered trademarks of IBM Corporation

The following are trademarks or registered trademarks of other companies.Intel is a trademark of Intel Corporation in the Unites States, other countries or both.Java and all Java-based trademarks and logos are trademarks of Sun Microsystems, Inc., in the United States and other countriesLinux is a registered trademark of Linux Torvalds in the United States other countries, or both. UNIX is a registered trademark of The Open Group in the United States and other countries.Microsoft, Windows and Windows NT are registered trademarks of Microsoft Corporation in the United States, other countries, or both.

Notes: Performance is in Internal Throughput Rate (ITR) ratio based on measurements and projections using standard IBM benchmarks in a controlled environment. The actual throughput that any user will experience will vary depending upon considerations such as the amount of multiprogramming in the user's job stream, the I/O configuration, the storage configuration, and the workload processed. Therefore, no assurance can be given that an individual user will achieve throughput improvements equivalent to the performance ratios stated here. IBM hardware products are manufactured from new parts, or new and serviceable used parts. Regardless, our warranty terms apply.All customer examples cited or described in this presentation are presented as illustrations of the manner in which some customers have used IBM products and the results they may have achieved. Actual environmental costs and performance characteristics will vary depending on individual customer configurations and conditions.This publication was produced in the United States. IBM may not offer the products, services or features discussed in this document in other countries, and the information may be subject to change without notice. Consult your local IBM business contact for information on the product or services available in your area.All statements regarding IBM's future direction and intent are subject to change or withdrawal without notice, and represent goals and objectives only.Information about non-IBM products is obtained from the manufacturers of those products or their published announcements. IBM has not tested those products and cannot confirm the performance, compatibility, or any other claims related to non-IBM products. Questions on the capabilities of non-IBM products should be addressed to the suppliers of those products.Prices subject to change without notice. Contact your IBM representative or Business Partner for the most current pricing in your geography.

* All other products may be trademarks or registered trademarks of their respective companies.

IBM System z

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Agenda

New Performance Support z/OS 1.10z/OS 1.11

Performance and Capacity Planning TopicsRSU InformationWLM RoutingzIIP and zAAP InformationzPCR InfoCompression InformationHardware InstrumentationHiperdispatchWLM Information

AddendumOlder APARs or Performance Information

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www.ibm.com/support/techdocs

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Contention Management Phase 3Promote units of work identified by exploiters for longer periods of timePromote to priority of highest-priority unit of work waiting for the held resource Info on promoted workloads recorded in RMF, SDSF DA and ENC panels

CPU Management of zIIPsWLM algorithms for adjusting dispatch priorities extended to zIIP workloads

Manage selected components in service class SYSTEMPrevent inadvertent misclassification of system address spaces regardless of the WLM Policy and protect system at high utilization

XCFAS, GRS, SMSPDSE, SMSPDSE1, CONSOLE, IEFSCHAS, IXGLOGR, SMF, and CATALOG

Support for 10 additional PB delay types and naming by subsystem

Extract the WLM service definition in XML formatInstall and activate a WLM service definition in XML format via a CIM Server

z/OS 1.10 Performance Items

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HiperDispatch improvements for zIIP processorsWill park/unpark zIIPs

New zAAP on zIIP supportz/OS CIM server processing will be eligible to run on the System z zIIPs

Java based CIM client apps on z/OS can already use zAAPsNew prefetch capability to provide perf improvements for XL C/C++ applications on z10

Reduce effects of memory latency by beginning to fetch data before it is known to be needed

VSCR improvements in the base z/OS GRS STAR mode sysplex-wide query requestsXML code page supportTCP/IP sockets processingAllocation changed to significantly reduce the storage required by the Eligible Device Table (EDT) for many I/O configurationsNew SMF fields to record more information on use of virtual, real, and aux storage above 2 GB and can help with capacity planning, performance management, and accounting

DFSMS support is planned for solid state drives (also called flash memory) on DS8000

z/OS 1.11 Performance Items

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RSU settings on z10The storage increment size on the z10 has increased from 64 to 256

RSU specifies the number of central storage units to be made available for storage reconfigurationStorage increment size is hardware dependent, based on hardware model, and possibly on amount of real storage installed on the CECAn unqualified value of 1-9999 (no M, G, T, or %) can have unexpected results

LPARs with RSU values should ensure the change in storage increment size does not adversely impact system performance

Over specification of the RSU parameter in IEASYSxx may cause significant performance overhead

During IPL system will issue messages IAR004I and IAR013I to warn of over specificationMight receive later message IAR005I to further warn of the potential performance impact

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RSU APAR - OA27801A new informational message IAR026I is added and will be issued during early IPL to notify of an RSU over-specified condition

Message will be issued when the RSU value specified is greater than the amount of real storage in the systemNew message followed by existing message IAR006A to identify invalid RSU value and prompt for a valid RSU or to hit enter to accept the defaultMessage will indicate the amount of real storage in the system

A large RSU value which is less or equal to the amount of real storage available in the system can still cause system performance problems, and the new message IAR026I will not be issued in this case The new message is as follows:

IAR026I THE RSU VALUE SPECIFIED EXCEEDS THE TOTAL AMOUNT OF REAL STORAGE AVAILABLE ON THIS SYSTEM: xxxxxxxxM

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Sysplex Routing - IWMSRSRS Function=SpecificEffect of PI on WLM Routing Recommendations

System Available Capacity

Original Server Weight

PI WLM Weight

SYS1 110 18 1.3 14

SYS2 100 16 0.8 16

SYS3 95 15 1.0 15

SYS4 95 15 2.0 8

400 64 53

SYS1 = 110/400 =.275 * 64 = 18 = 18 / 1.3 = 14

Example assumes a 4-way SysplexIf the server specific weight is >1 the weight is divided by the PIConsequently the sum of all weight is no longer normalized to 64WLM server weight influences the distribution of work across the sysplex by the subsystem

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WLM Routing ServicesOA27940

PI Factor used for WLM Routing service IWMSRSRS Function=SPECIFIC can have a negative impact on the routing recommendation if a very aggressive but almost unachievable goal is set

This type of goal has a PI which indicates the work is missing its goal even if the work is receiving very good serviceThe PI>1 can cause the routing service to route work away from the server

New IEAOPTxx parameter introduced called RTPIFACTORSpecified as a value from 0-100RTPIFACTOR=0 PI is not consideredRTPIFACTOR=100 PI is fully considered RTPIFACTOR=(1:99) PI impact is reduced accordingly

Recommend rework the goals of the affected service classes rather than use this parameter

Use this setting only if a negative effect is seen, otherwise do not code in the IEAOPTxxThis is a global setting and applies to all users of IWMSRSRS Function=SPECIFIC

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WLM Routing ServicesOA27063 - Doc APAR

For z/OS v1.9 and v1.10 IEAOPTxx parameter WASROUTINGLEVEL has incorrect default specified in the MVS Init & Tuning, SA22-7592-xxWASROUTINGLEVEL= 0 | 1