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IBM Advanced Technical Support
z/OS Performance "Hot" TopicsSHARE - Winter ConferenceMarch, 2009EWCPSession: 2500
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 1.11 (Preview) and z/OS 1.10
Performance and Capacity Planning TopicsRSU InformationGetmain ChangesWLM RoutingzIIP and zAAP InformationCapacity Planning InfoCycle SteeringCompressionHiperdispatchDumping Performance
AddendumOlder APARs or Performance Information
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www.ibm.com/support/techdocs
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HiperDispatch improvements for zIIP processorsz/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 Sysplex Distributor to use new and improved WLM interfaces for more efficient workload distribution in a sysplexed multi-tiered z/OS server environment
z/OS 1.11 Performance Items
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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 namimg 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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RSU settings on z10The storage increment size on the z10 has increased from 64 to 256LPARs with RSU values should ensure the change in storage increment size does not adversely impact system performanceExample
z9 had an 8GB LPAR with an RSU value of 64 meant 4GB of the storage was considered reconfigurablez10 with the same 64 RSU value meant 16GB would be reconfigurable
Entire Central Storage allocation Impact is a lot of high impact page movementVery low capture ratios
OA27801New system health check to detect RSU over-specification conditions and issue a non-scrolling message warning of the potential impact
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GETMAIN Enhancements in z/OS 1.10As of z/OS 1.10, small GETMAINs in user region private are satisfied from the beginning of the page instead of from the end of the page
Vendor and legacy code may wrongly assumed the GETMAINed area would contain zeroes which may cause overlays or other incorrect processing GETMAIN change was undocumented in z/OS 1.10
There was an undocumented DIAGxx setting 'NUCLABEL ENABLE(IGVGPVTN)' to allow GETMAIN to work as it did previously
The change was made to improve performance of DB2 open processing for a large number of datasets
OA27291 - Behavior of GETMAIN for low private storage poolsDefault behavior will remain the same as previous releasesDIAGxx keyword provided as a documented method to switch to new GETMAIN behavior
VSM USEZOSV1R9RULES(YES|NO), Provide new dispay command and IPCS support to determine the setting
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z/OS 1.10 RMF Enhancements
RMF Monitor III provides new reports about spin and suspend locksSuspend Lock report will display the address spaces which hold locks and which are suspendedSpin Lock report will display how often global locks are held and who is spinning
Reporting of lock statistics is intended to help analyze lock contention in the system
RMF Overview Report Selection Menu Selection ===>
Enter selection number or command for desired report.
Basic Reports1 WFEX Workflow/Exceptions (WE)2 SYSINFO System information (SI)3 CPC CPC capacity
Detail Reports4 DELAY Delays (DLY)5 GROUP Group response time breakdown (RT)6 ENCLAVE Enclave resource consumption and delays (ENCL)7 OPD OMVS process data8 ZFSSUM zFS summary (ZFSS)9 ZFSACT zFS activity (ZFSA)10 SPACEG Storage space (SPG)11 SPACED Disk space (SPD)12 LOCKSP Spin locks (LSP)13 LOCKSU Suspend locks (LSU)
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zIIPs and VIPADISTRIBUTEPrior to z/OS v1.9 capacity of specialty CPs not used by WLM when calculating weights for:
Sysplex Distributorz/OS Load Balancing Advisor
SERVERWLM - server specific weightsUses composite WLM weights and factors in capacity of specialty CPs based on the portion they are used by the specific server address spaceNo configuration change needed for SERVERWLM
BASEWLMUses composite WLM weights and factors in capacity of specialty CPs based on the portion they are used on each system (whole system rather than specific server address spaces)Uses separate WLM weights from all processor types and combines them based on CS configuration on how each processor type should impact the combined weights
Options to configure the mix of processor types needed by the application workload provided by Comm Server
VIPADISTRIBUTE ... BASEWLM PROCTYPE(CP=3, ZAAP=1,ZIIP=0)
Benefit: Better distribution of work with Specialty CP content to LPARs with the most available Specialty CP capacity
Improves overall throughput and reduce TCOIncreases utilization of zIIPs and zAAPs
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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
OA27063 - Doc APARFor z/OS v1.9 and v1.10 IEAOPTxx parameter WASROUTINGLEVEL has incorrect default specified in the MVS Init & Tuning, SA22-7592-xxWASROUTINGLEVEL= 0 | 1
Specify 0This is the default WLM uses most advanced routing algorithm supported by ALL systems in the sysplex
Specify 1 WLM uses the round robin algorithm This option if chosen should be the same for all systems in the sysplex
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LPAR
z/VM
LPAR
z/VSE
LPAR
z/VM
LPAR
z/OS
z/VSE LinuxLinux
zAAP zAAP zAAP zIIP zIIP ICF ICFCP CP CP CP CP IFL IFL IFL IFL
LinuxLinuxLinux
Linux ProductionDev/Test and Optional Failover
z/OS and/or z/VSE Production
LPAR
z/OS
LPAR
CFCC
IFL
IBM System z10
z/VM-mode LPARCFCC CMSz/OS
LPAR
z/VM
LPAR
z/VSE
LPAR
z/VM
LPAR
z/OS
z/VSE LinuxLinux
zAAP zAAP zAAP zIIP zIIP ICF ICFCP CP CP CP CP IFL IFL IFL IFL
LinuxLinuxLinux
Linux ProductionDev/Test and Optional Failover
z/OS and/or z/VSE Production
LPAR
z/OS
LPAR
CFCC
IFL
IBM System z10
z/VM-mode LPARCFCC CMSz/OS
New LPAR type for IBM System z10: z/VM-modeAllows z/VM V5.4 users to configure all CPU types in a z10 LPAR
Offers added flexibility for hosting mainframe workloadsAdd IFLs to an existing standard-engine z/VM LPAR to host Linux workloadsAdd CPs to an existing IFL z/VM LPAR to host z/OS, z/VSE, or traditional CMS workloadsAdd zAAPs and zIIPs to host eligible z/OS specialty-engine processingTest integrated Linux and z/OS and z/VSE solutions in the same LPAR
No change to IBM software licensingSoftware continues to be licensed according to CPU type
z/VM-Mode LPAR Support for IBM System z10
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In z/OS 1.10 HiperSockets has been enhanced for zIIP exploitation
Specifically, z/OS Communications Server allows the HiperSockets Multiple Write operation for outbound large messages (originating from z/OS) to be performed by a zIIP
Both sending and receiving LPAR experience fewer I/O interruptsAllows the receiving LPAR to process much more data per I/O interruptAsynchronously moves data without blocking the sending applicationMay help reduce general CPU utilization even without zIIP
This capability helps make highly secure, available, virtual HiperSockets networking more attractive
Application workloads based on XML, HTTP, SOAP, Java, etc. as well as traditional file transfer, can benefit from this function by helping to lower general purpose processor utilization of such traffic
Available on z/OS V1.10 and System z10 only
zIIP Assisted HiperSockets for Large Messages
Data DataDataDataData
Multi Write operation
Large message outboundfrom z/OS
Data DataDataDataData
Multi Write operation
Large message outboundfrom z/OS
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zAAPs and zIIPS
APAR OA23479 - HIPERIn z/OS 1.9 a change resulted in too few SIGPs to be issued resulting in poor performance on zAAPs and zIIPs
APAR OA23828 - New Functionz/OS 1.8 and aboveWhen XML System Services (XML SS) are called in task mode 100% of the CPU used to parse a document are eligible for offload to a zAAPWhen XML System Services are called in enclave SRB mode:
If the calling SRB was not zIIP eligible the XML SS CPU was not eligible for offloadIf the calling SRB was zIIP eligible the XML SS CPU was offloaded at the same percentage as the calling application
Change enclave SRB processing to allow the XML SS CPU to be 100% eligible for zIIP offload
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z10 System Design and Workload Characteristicsz10 has the potential for greater workload variability
z9 ECCPU
1.7 GhzSuperscalar
CachesL1 private 256k i, 256k dL2 shared 40 MBs / bookBook interconnect: ring
z10 ECCPU
4.4 GhzRedesigned pipelineSuperscalar
CachesL1 private 64k i, 128k dL1.5 private 3 MBsL2 shared 48 MBs / bookBook interconnect: star
MEMORY
L2 CACHE
CPU
L1
. . .CPU
L1
CPU
L1
MEMORY
L2 CACHE
CPU
L1.5
. . .CPU
L1.5
CPU
L1.5L1 L1 L1
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Workload CharacteristicsWorkload Characteristics
CPUInstructions
MixSequenceBranch characteristics
Task dispatch profileLocked in or chatty
MemorySizeLocality of referenceMultiprogramming level
I/O rate
Current z/OS LSPR workload suite
ODE-BCB-LWASDBOLTP-TOLTP-WMIXED
CPU Use Profile I/O Memory SubsysODE-B heavy appl, light OS light lightCB-L heavy appl, light OS light lightWASDB medium appl and OS light moderateOLTP-T medium appl and OS heavy moderateOLTP-W medium appl and OS moderate stress
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Customer production workloads don't look like the LSPR benchmarksInstead use mixes or blends of the different primitives
Most common workload mix is LoIO MixWe use the I/O rate per used MSUs (LoIO Mix) as an indicator for which of the mixes are a most likely match and those which are the leastI/O was an externally available metric to describe workload characteristics of under the cover behavior such as instruction mix, buffer hit rate, etc.)Low I/O was an indicator of CPU intensity, not a guarantee
Processor migrations need to be understood based on the +/- 5% zPCR projections
For example:A system with a expected ITRR of 1.02, actually needs to be positioned as 0.97 of the current capacityAssess the capacity relationship if the processor is actually 3% smaller
z10 Capacity Planning
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Capacity Planning Studies
A new workload mix, DI-MIX, is introduced (Data Intensive Mix)Supported in zPCR v5.1d and zCP3000 (07/11/2008)New mix is also a Low I/O workload
Has all the characteristics of LO-IO Mix but it also has the added attribute of intense memory accesses
DI-Mix will provide the most conservative view of capacityMethod to check the outer band (lower) of performance
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SMF23 Enhancements
OA22414 - New FunctionFor z/OS 1.8 and beyondSupported on any IBM System z or IBM zSeries Processor
Adds new workload characterization counters to SMF 23 recordsTCB and SRB dispatches per CPU RSM Services intensity by tracking number of getmains, first reference page faults, non first reference faults, page fixes, etcOverall I/O rates
Better workload profiling data to enhance workload-mix selection for LSPR and zPCR
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WP101208 - Running IBM System z at High Utilization System z runs a diverse mix of customer applications and exploits the full capability of the underlying hardware while meeting customer SLA
WLM, IRD, PR/SM, Parallel Sysplex, etc.
Can Any Single Workload Be Run At 100% CPU Busy?The simple answer is no
Queuing theory shows under many conditions described by arrival rate and service time distribution, as a server approaches 100% the queue of work waiting to be processed grows exponentially as does response timeHomogeneous, transaction processing workloads behave like this
Is there a growth in CPU time per transaction at higher utilization?The simple answer is yes
Transactions processed on a system share the physical hardware resources (CPs, caches, memory buses) and software resources (z/OS, subsystems) on the systemOne might presume if a transaction rate of X drives a processor at 50% busy, then at 100% the processor would be able to support 2X the transaction rate, however, this will not be the case
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System z: High Availability - Cycle SteeringCycle steering mode is entered whenever the Mulit-Chip Module (MCM) has a cooling issue
Often due to a Modular Refrigeration Unit (MRU) failureDone to protect the processor from failure
Processor will reduce cycle speed and notifies operating systemReduction in Speed is typically from 4-6%Higher reported SU/SEC impact are most likely due to not having MCL patch supplied in DR67L MCL211.G40965 in Bundle37
z/OS will adjust to the lower speedIssues ENF 20, Changes SU/SEC value (R72MADJ), internal reactivate the WLM policy, stop/restart intervals, issues a SMF 99 subtype 10 record to audit the speed change, issues IWM063I at each change in processor speed
The MSU rating of the processor is not changedReduction in processor speed seen as temporary error situation
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Compression on System z10z9 - Compression dictionary is cached in standard L1 processor cache
Thus can interfer with all other work on the systemz10 - Each CP has a compression engine with a 16K cache
Removes compression impact from other workloads but concentrates any negative impacts to just the compression work unitsCompression work may have a lower ITRR than expected on the z10
z10 CPU Measurement FacilityNew hardware instrumentation facility available on z10 GA2 New z/OS component - Hardware Instrumentation Facility (HIS)
Requires APARs OA25755, OA25750, and OA25773CPU MF provides support built into the processor hardwarePotential Future Uses:
Better workload characterizationISV Product ImprovementsApplication Tuning
Session 2536: WSC Short Stories and Tall Tales, Thurs - 1:30 PM Room 19A
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z/OS HiperDispatch ModeImproved dispatching can help reduce the effects of memory latency to improve performance and reduce CPU time
Better access to hardware cacheManage work across fewer logical CPs
Correct dispatch priorities are critical
Processors will not have equal logical share, but rather a vertical share:High: 100% shareMedium: 0-100% share, the remainder after Vertical High shareLow: 0-100% share, not needed for weight and is discretionary
IRD Vary CPU management is disabled and replacedLogical CPs provided based on weight, workload demand, and available capacity
New knowledge of processor topology when dispatching workWorks with PR/SMtm to build a strong affinity between logical and physical processors
Recommendation is to enable with the installation of the z10If HD=NO ensure sufficient capacity to handle the loss of performance
Not supported for z/OS guests under z/VM
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z/OS HiperDispatch Mode - MVS BUSYRMF APAR OA24074
Definition of MVS Busy Time is changed to not include PARKED timeMVS Busy is an indication of latent demand due to LPAR weight enforcementIncreased PARKED time is now also an indication of latent demand due to LPAR weight enforcement
MVS Busy Time (Wait Time + Parked Time) Online Time - * 100=
(Online Time - Parked Time) -CPU 2097 MODEL 725 HIPERDISPATCH=YES0---CPU--- ---------------- TIME % ---------------- LOG PROC --I/O INTERRUPTS-- NUM TYPE ONLINE LPAR BUSY MVS BUSY PARKED SHARE % RATE % VIA TPI 0 CP 100.00 65.16 65.61 0.00 100.0 120.7 37.54 1 CP 100.00 74.83 75.19 0.00 100.0 3397 6.45 2 CP 100.00 56.93 57.31 0.00 100.0 1971 2.04 3 CP 100.00 63.33 64.63 0.00 100.0 2566 3.26 4 CP 100.00 70.06 74.21 0.00 50.0 218.9 20.69 5 CP 100.00 0.01 ----- 100.00 0.0 0.00 0.00 6 CP 100.00 0.00 ----- 100.00 0.0 0.00 0.00 7 CP 100.00 0.00 ----- 100.00 0.0 0.00 0.00 8 CP 100.00 0.00 ----- 100.00 0.0 0.00 0.00 9 CP 100.00 0.00 ----- 100.00 0.0 0.00 0.00 A CP 100.00 0.00 ----- 100.00 0.0 0.00 0.00 B CP 100.00 0.00 ----- 100.00 0.0 0.00 0.00 TOTAL/AVERAGE 27.53 67.39 450.0 8273 5.24
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Hiperdispatch and zPCRWhen building the zPCR model from an RMF report zPCR cannot determine the number of actual logical processors unparked in an LPAR when running hiperdispatch=YES
Requires the user to manually determine the number of unparked CPs Using the number reported in the RMF report would overstate the number of logicalsCannot determine the unparked values for other LPARs
IRD users and hiperdispatch=NO environment the logical CPs are correctly determined by zPCR
IRD uses the config CPU command and so the actual environment is changedThe SMF70 record from any LPAR on a CEC can determine the actual logical CPs defined for all LPARs
Warning message is issued when Hiperdispatch=YES systems are read into zPCR
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New WLM Toolshttp://www-03.ibm.com/servers/eserver/zseries/zos/wlm/tools/wlmque.html
WLMOPTDisplays the current IEAOPT settingsIdentifies the currently active OPT member, when it was installed, and the settings of all OPT parameters
WLMQUEISPF based tool to display the application environments currently being used on your z/OS systemView the number of started and active server address spaces, and the service classes being used as work queues for the application environmentsTool can be used for any kind of application environment from WebSphere, DB2 or user specified types and applications
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TD104728 - z/OS Availability: Managing SVC Dumps to Mitigate Exhausting the Paging Subsystem
Planning is required to ensure proper operation of SVC DumpToo little AUX can cause a system outage or workload issues
Discusses how to set MAXSPACE parameter Shows how to review RMF Paging data to estimate how big a MAXSPACE your system can support
Discusses how big a MAXSPACE parameter is neededImpacts of Common and size of largest address spaces needing to be dumped
Importance of ensuring a well configured AUX subsystem to support a large dump of multiple address spaces, or multiple dumps taken quickly in progression
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SVC Dump PlanningAs SVC Dumps grow in size it is important to properly define dump data sets
Especially as CHNGDUMP MAXSPACE parameters increase
Do not specify multi-volume dump data sets as they are not supported by z/OS Applies to both SYS1.DUMPxx and dynamically allocated data setsCan cause SWA corruption in the DUMPSRV address spaceWould only support a dump of 65535 TRKS, any dump requiring more than this would have a dynamic allocation failure
IGD17051I ALLOCATION FAILED FOR DATA SET LSE.SVC090.AMMLP1.D020321.T10 4951.S00002 , PRIMARY SPACE EXCEEDS 65535 TRKS
Specify dump data sets as SMS managed, using a Data Class with the Extended Format attribute and use the Storage Class attribute Sustained Data Rate to get stripes
3 volumes ("stripes") should be sufficient for a dump data set
Additional DocFLASH10182 - z/OS Performance: SVC Dump PerformanceDFSMS Storage Administration Reference, SC26-7402-09DOC APAR - OA22623
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Addendum
Older flashes which should still be understood, or make you go Hmmmm. APARs which are still causing issues, even though they are old.
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z/OS 1.9 Performance Items
1. Provide automatic CPU promotion for canceled jobsCanceled job may be holding resources needed elsewhere, (storage, ENQ, latch), but if dispatch priority is not high enough Cancel processing cannot run
2. Provide throughput to blocked workloadsDispatch low priority workloads from time to time Helps resolve resource contention for workloads without resource management implemented
IMP 1 System IMP 3 IMP 2 IMP 5
IMP 3
IMP 3
Has resource xNeeds resource x
Getting CPU
Not Getting CPU
High Priority work is now blocked by lower priority work
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Blocked Workloads
New IEAOPTxx parametersBLWLTRPCT
Percentage of the CPU capacity of the LPAR to be used for promotionIn tenths of a percent (0.1%)Range: 0 to 200 (0.1% to 20%)Default: 5
BLWLINTHDStarvation threshold in seconds. Amount of time when an address space or enclave has not received CPU service within this time and is considered blockedRange: 5 seconds to 65535 seconds (18+ hours)Default: 20 seconds
RMF Reports updated with informationCPU ActivityWorkload Activity
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WSC FLASH10609 - Blocked Workload Support BLOCKED WORKLOAD ANALYSIS BLWLTRPCT (%) 0.5 PROMOTE RATE: DEFINED 14 WAITERS FOR PROMOTE: AVG 0.010 BLWLINTHD 60 USED (%) 4 PEAK 1
PROMOTE RATE: DEFINED - Number of blocked work units which may be promoted in their dispatching priority per second
PROMOTE RATE: USED (%) - The utilization of the defined promote rate during the reporting interval
It demonstrates how many trickles were actually given away (in percent of the allowed maximum) for the RMF interval
APAR OA22443New recommended defaults of BLWLINTHD=20 and BLWLTRPCT=5Applies to z/OS 1.9, 1.8 and 1.7
Recommended for the IEAOPTxx member of SYS1.PARMLIB to not code parameters specifying default values.
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