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Keeping Up with z/OS’ Alphabet Soup. Darrell Faulkner Computer Associates Development Manager NeuMICS . Objectives. Integrated Coupling Facility ( ICF ) and Integrated Facilities for LINUX ( IFL ) PR/SM and LP s Intelligent Resource Director ( IRD ) IBM License Manager ( ILM )

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keeping up with z os alphabet soup

Keeping Up with z/OS’ Alphabet Soup

Darrell Faulkner

Computer Associates

Development Manager

NeuMICS

objectives
Objectives
  • Integrated Coupling Facility (ICF) and Integrated Facilities for LINUX (IFL)
  • PR/SM and LPs
  • Intelligent Resource Director (IRD)
  • IBM License Manager (ILM)
  • Capacity Upgrade on Demand (CUoD)
  • Conclusions
acronyms
Acronyms

CF - Coupling Facility

CP - Central Processor

CPC - Central Processor Complex

ICF- Integrated Coupling Facility

IFL - Integrated Facility for LINUX

PR/SM- Processor Resource/Systems Manager

HMC - Hardware Management Console

LLIC- LPAR Licensed Internal Code

Logical CP - Logical Processor

LP - Logical Partition

LPAR - Logical Partitioning (LPAR mode)

PU- Processor Unit

icf and ifl
ICF and IFL
  • Beginning with some IBM G5 processor models, the ability to configure PUs (Processing Units) as non-general purpose processors
  • Benefit - Does not change model number hence no software licensing cost increase

IFL - Integrated Facility for LINUX

ICF - Integrated Coupling Facility

z900 models 2064 101 109

PU

PU

PU

PU

PU

PU

PU

PU

PU

PU

PU

PU

PU

All contain a 12 PU MultiChip Module (MCM)

CPC MEMORY

Central (General) Processor

CP

Processing Unit (PU)

Integrated Coupling Facility

ICF

Integrated Facility for LINUX

IFL

System Assist Processor

SAP

z900 Models 2064-(101-109)
z900 model 2064 105

PU

PU

PU

PU

CP

CP

CP

PU

SAP

SAP

CP

CP

All contain a 12 PU MultiChip Module (MCM)

CPC MEMORY

CP

Central (General) Processor

z900 Model 2064-105

5 PUs Configured as CPs = Model 105

CPs Defined = Model Number

z900 model 2064 1057

CP

IFL

IFL

CP

CP

CP

CP

PU

SAP

SAP

SAP

One PU always left unconfigured for “spare”

CPC MEMORY

5 PUs Configured as CPs = Model 105

CPs Defined = Model Number

CP

Central (General) Processor

ICFs, IFLs, and SAPs do not incur software charges

ICF

ICF

ICF

IFL

z900 Model 2064-105
icfs and ifls
ICFs and IFLs

IBM SMF Type 70 subtype 1 record - CPU Identification Section

There is one section per EBCDIC name that identifies a CPU type. 'CP' and 'ICF', with appropriate trailing blanks, are examples of EBCDIC names describing a General Purpose CPU and an Internal Coupling Facility CPU, respectively.

Name = SMF70CIN

Length = 16 EBCDIC

Description = CPU-identification Name

Offsets 0 0

As of z/OS Version 1 Release 2, both IFLs and ICFs are represented by ‘ICF’ in the SMF type 70 CPU ID Section

IFL - Integrated Facility for LINUX

  • CP = Central Processor

ICF - Integrated Coupling Facility

pr sm lpar
PR/SM LPAR
  • Allows up to 15 images (LPs) per CPC
  • Different control programs on images
    • (z/OS, z/VM, Linux, CFCC etc.)
  • Each LP (image) assigned CPC resources:
    • Processors (CPs) (referred to as “logical CPs”)
    • Memory
    • Channels
  • Each LP either DEDICATED or SHARED
  • Logical CP = Logical Processor
  • LP = Logical Partition
  • CPC = Central Processor Complex
pr sm benefits
PR/SM Benefits
  • Protection/isolation of business critical applications from non-critical workloads
  • Isolation of test operating systems
  • Workload Balancing
  • Different operating systems -- same CPs
  • Ability to guarantee minimum percent of shared CP resource to each partition
  • More “white space” – the ability to handle spikes and unpredictable demand
lp configuration decisions
LP Configuration Decisions
  • LP definitions entered on HMC
    • Dedicated or not-dedicated (shared)
    • Logical processors (initial, reserved)
    • Weight (initial, min, max)
    • Capped or not-capped
    • CPC memory allocation
    • I/O Channel distribution/configuration
    • More
  • HMC = Hardware Management Console
  • LP = Logical Partition
  • CPC = Central Processor Complex
dedicated lps

HMC Image Profile

ZOS1

Dedicated LPs
  • LPs logical CPs are permanently assigned to specific CPC physical CPs
  • Less LPAR overhead (than shared LPs)
  • Dedicated LPs waste physical (CPC) processor cycles unless 100% busy
  • When less than 100% busy, the physical CPs assigned to dedicated LPs are IDLE
  • Logical CP = Logical Processor
  • LP = Logical Partition
  • CPC = Central Processor Complex
lpar mode dedicated

LCP

CP

CP

CP

CP

LCP

LCP

LCP

CP

LCP

LPAR MODE - Dedicated

PR/SM LPAR LIC

CPC MEMORY

ZOS1

ZOS2

ZOS1 Image - 3 Dedicated Logical ProcessorsZOS2 Image - 2 Dedicated Logical Processors

Same problem as basic mode - Unused cycles wasted

  • LCP = Logical CP = Logical Processor
shared lps
Shared LPs

HMC Image Profile

ZOS1

shared lps15
Shared LPs

HMC Image Profile

ZOS2

lpar mode shared

LCP

LCP

CP

CP

CP

CP

CP

LCP

LCP

LCP

CPC MEMORY

ZOS1

ZOS2

Shared CP Pool

LCP

LCP

LCP

ZOS1 Image

5 Logical CPs

Weight 400

ZOS2 Image

3 Logical CPs

Weight 100

LPAR Mode - Shared

PR/SM LPAR LIC

  • LCP = Logical CP = Logical Processor
lpar dispatching
LPAR Dispatching

What does LLIC (LPAR Licensed Internal Code) Do?

  • LCPs are considered dispatchable units of work
  • LCPs placed on ready queue
  • LLIC executes on physical CP
    • it selects a ready LCP and
    • dispatches it onto real CPs
  • z/OS executes on physical CP until timeslice expires (12.5-25 milliseconds) or until z/OS enters a wait state
  • Environment saved, LLIC executes on freed CP
  • If LCP still ready (used timeslice), it is placed back on ready queue
  • LLIC = LPAR Licensed Internal Code
  • CP = Central Processor
  • LCP = Logical CP = Logical Processor
selecting logical cps
Selecting Logical CPs
  • Priority on the “ready” queue is determined by PR/SM LIC
    • Based on LP logical CP “actual” utilization versus “targeted” utilization
  • Targeted utilization is determined as a function of #LCPs and LP Weight
    • LP weight is a user specified number between 1 and 999 (recommended 3 digits)
  • LP = Logical Partition
  • LLIC = LPAR Licensed Internal Code
  • LCP = Logical CP = Logical Processor
  • CP = Central Processor
lp weights shared pool

LCP

LCP

LCP

CP

CP

CP

CP

CP

LCP

LCP

Shared CP Pool

LCP

LCP

LCP

LP Weights -Shared Pool %

PR/SM LPAR LIC

CPC MEMORY

ZOS1

ZOS2

400

100

ZOS1 Image

ZOS2 Image

  • Total of LP Weights = 400 + 100 = 500
  • ZOS1 LP Weight % = 100 * 400/500 = 80%
  • ZOS2 LP Weight % = 100 * 100/500 = 20%
  • LP = Logical Partition
  • LCP = Logical CP = Logical Processor
lp weights guarantee pool cp share
LP Weights Guarantee“Pool” CP % Share
  • Weight assigned to each LP defined as shared
  • All active LP weights summed to Total
  • Each LP is guaranteed a number of the pooled physical CPs based on weight% of Total
  • Based on #shared logical CPs defined for each LP & LP weight%, LLIC determines the “ready queue” priority of each logical CP
  • Weight priority enforced only when contention!
  • LP = Logical Partition
  • LLIC = LPAR Licensed Internal Code
  • LCP = Logical CP = Logical Processor
  • CP = Central Processor
lp target cps

LCP

CP

CP

CP

CP

CP

LCP

LCP

LCP

LCP

Shared CP Pool

LCP

LCP

LCP

  • CP = Central Processor
  • LP = Logical Partition
  • LCP = Logical CP = Logical Processor
LP Target CPs

PR/SM LPAR LIC

CPC MEMORY

ZOS1

ZOS2

400

100

ZOS1 Image

ZOS2 Image

  • ZOS1 LP Weight % = 80%
  • Target CPs = 0.8 * 5 = 4.0 CPs
  • ZOS2 LP Weight % = 20%
  • Target CPs = 0.2 * 5 = 1.0 CPs
lp logical cp share

CP = Central Processor

  • LP = Logical Partition
  • LCP = Logical CP = Logical Processor
LP Logical CP share
  • ZOS1 LP is guaranteed 4 physical CPs
    • ZOS1 can dispatch work to 5 logical CPs
    • Each ZOS1 logical CP gets 4/5 or 0.8 CP
    • ZOS1 effective speed = 0.8 potential speed
  • ZOS2 LP is guaranteed 1 physical CP
    • ZOS2 can dispatch work to 3 logical CPs
    • Each ZOS2 logical CP gets 1/3 or 0.333 CP
    • ZOS2 effective speed = 0.333 potential speed
impact of changing weights
Impact of Changing Weights
  • An active LP’s weight can be changed non-disruptively using system console
    • Increasing an LP’s weight by “x”, without any other configuration changes, increases its pooled CP share at the expense of all other shared LPs
    • This is because the TOTAL shared LP weight increased, while all other sharing LPs weights remained constant:

LPn weight LPn weight >

TOTAL (TOTAL + x)

  • LP = Logical Partition
  • CP = Central Processor
changing lpar weights

CP

LCP

CP

CP

CP

CP

LCP

LCP

LCP

LCP

PR/SM LPAR LIC

Shared CP Pool

CPC MEMORY

ZOS1

ZOS2

LCP

LCP

LCP

ZOS1 Image

ZOS2 Image

  • Total of LP Weights = 400 + 200 = 600
  • ZOS1 LP Weight % = 100 * 400/600 = 66.67%
  • ZOS2 LP Weight % = 100 * 200/600 = 33.33%
  • CP = Central Processor
  • LP = Logical Partition
  • LCP = Logical CP = Logical Processor
Changing LPAR Weights

100

400

+

100

lp target cps25

LCP

LCP

LCP

LCP

CP

CP

CP

CP

CP

LCP

Shared CP Pool

LCP

LCP

LCP

ZOS1 Image

ZOS2 Image

  • ZOS1 Weight % = 66.67%
  • Target CPs = 0.667 * 5 = 3.335 CPs
  • ZOS2 LP Weight % = 33.33%
  • Target CPs = 0.333 * 5 = 1.665 CPs
  • CP = Central Processor
  • LP = Logical Partition
  • LCP = Logical CP = Logical Processor
LP Target CPs

PR/SM LPAR LIC

CPC MEMORY

ZOS1

ZOS2

400

200

lp logical cp share26

CP = Central Processor

  • LP = Logical Partition
  • LCP = Logical CP = Logical Processor
LP Logical CP share
  • ZOS1 LP is guaranteed 3.335 physical CPs
    • ZOS1 can dispatch work to 5 logical CPs
    • Each ZOS1 logical CP gets 3.335/5 or 0.667 CP
    • ZOS1 effective speed = 0.667 potential speed
  • ZOS2 LP is guaranteed 1.665 physical CP
    • ZOS2 can dispatch work to 3 logical CPs
    • Each ZOS2 logical CP gets 1.665/3 or 0.555 CP
    • ZOS2 effective speed = 0.555 potential speed
changing logical cp count

CP = Central Processor

  • LP = Logical Partition
  • LCP = Logical CP = Logical Processor
Changing Logical CP Count
  • An active LP’s logical CPs can be increased or reduced non-disruptively
  • Changing the number of logical CPs for a shared LP increases or decreases the LP work “potential”
    • Changes z/OS and PR/SM overhead
    • Does not change the % CPC pool share
    • Changes the LP logical CP “effective speed”
  • CPC = Central Processor Complex
adding logical cps

L

LCP

LCP

LCP

LCP

CP

CP

CP

CP

CP

L

L

L

L

LCP

PR/SM LPAR LIC

Shared CP Pool

CPC MEMORY

ZOS1

ZOS2

LCP

LCP

LCP

LCP

WEIGHT %

UNCHANGED!!

Adding Logical CPs

400

100

+

ZOS1 Image

ZOS2 Image

  • Total LP Weights = 400 + 100 = 500
  • ZOS1 LP Weight % = 100 * 400/500 = 80%
  • ZOS2 LP Weight % = 100 * 100/500 = 20%
adding logical cps29

CP

CP

CP

CP

CP

PR/SM LPAR LIC

Shared CP Pool

CPC MEMORY

ZOS1

ZOS2

  • CP = Central Processor
  • LP = Logical Partition
  • LCP = Logical CP = Logical Processor

TARGET CPs UNCHANGED!!

Adding Logical CPs

400

100

LCP

LCP

LCP

LCP

LCP

LCP

LCP

LCP

LCP

ZOS1 Image

ZOS2 Image

  • ZOS1 Weight % = 80%
  • Target CPs = 0.8 * 5 = 4.0 CPs
  • ZOS2 LP Weight % = 20%
  • Target CPs = 0.2 * 5 = 1.0 CPs
adding logical cps30

CP = Central Processor

  • LP = Logical Partition
  • LCP = Logical CP = Logical Processor
Adding Logical CPs
  • ZOS1 LP is guaranteed 4 physical CPs
    • ZOS1 can dispatch work to 5 logical CPs
    • Each ZOS1 logical CP gets 4/5 or 0.8 CP
    • ZOS1 effective speed = 0.8 potential speed
  • ZOS2 LP is guaranteed 1 physical CP
    • ZOS2 can dispatch work to4logical CPs
    • Each ZOS2 logical CP gets 1/4 or 0.25 CP
    • ZOS2 effective speed = 0.25 potential speed

ZOS2 Effective logical CP speed DECREASED!!

subtracting logical cps

LCP

LCP

LCP

LCP

LCP

CP

CP

CP

CP

CP

PR/SM LPAR LIC

Shared CP Pool

CPC MEMORY

ZOS1

ZOS2

LCP

LCP

LCP

LCP

WEIGHT %

UNCHANGED!!

  • CP = Central Processor
  • LP = Logical Partition
  • LCP = Logical CP = Logical Processor
Subtracting Logical CPs

400

100

-

ZOS1 Image

ZOS2 Image

  • Total LP Weights = 400 + 100 = 500
  • ZOS1 LP Weight % = 100 * 400/500 = 80%
  • ZOS2 LP Weight % = 100 * 100/500 = 20%
subtracting logical cps32

LCP

CP

CP

CP

CP

LCP

CP

LCP

LCP

LCP

LCP

PR/SM LPAR LIC

Shared CP Pool

CPC MEMORY

ZOS1

ZOS2

LCP

  • CP = Central Processor
  • LP = Logical Partition
  • LCP = Logical CP = Logical Processor

TARGET CPs UNCHANGED!!

Subtracting Logical CPs

400

100

ZOS1 Image

ZOS2 Image

  • ZOS1 Weight % = 80%
  • Target CPs = 0.8 * 5 = 4.0 CPs
  • ZOS2 LP Weight % = 20%
  • Target CPs = 0.2 * 5 = 1.0 CPs
subtracting logical cps33

CP = Central Processor

  • LP = Logical Partition
  • LCP = Logical CP = Logical Processor
Subtracting Logical CPs
  • ZOS1 LP is guaranteed 4 physical CPs
    • ZOS1 can dispatch work to 5 logical CPs
    • Each ZOS1 logical CP gets 4/5 or 0.8 CP
    • ZOS1 effective speed = 0.8 potential speed
  • ZOS2 LP is guaranteed 1 physical CP
    • ZOS2 can dispatch work to 2logical CPs
    • Each ZOS2 logical CP gets 1/2 or 0.5 CP
    • ZOS2 effective speed = 0.5 potential speed

ZOS2 Effective logical CP speed INCREASED!!

logical cps how many
Logical CPs - How Many?
  • Both z/OS and PR/SM overhead minimized when LCP count is equal to the physical CP requirements of the executing workload
  • The number of LCPs online to an LP is correct … sometimes …
    • When the LP is CPU constrained, too few
    • When the LP is idling, too many
    • When the LP is about 100% busy, just right!
  • Ideally, effective LCP speed = 1.0
  • CP = Central Processor
  • LP = Logical Partition
  • LCP = Logical CP = Logical Processor
lp configuration decisions35
LP Configuration Decisions
  • LP definitions entered on HMC
    • Dedicated or not-dedicated (shared)
    • Logical processors (initial, reserved)
    • Weight (initial, min, max)
    • Capped or not-capped
    • CPC memory allocation
    • I/O Channel distribution/configuration
    • etc
  • HMC = Hardware Management Console
  • CPC = Central Processor Complex
lp hard capping

HMC Image Profile

LP “Hard” Capping
  • Initial weight enforced
  • LLIC will not allow LP to use more than guaranteed shared pool % even when other LPs idle
  • Dynamic change to capping status
    • Capped or not capped
    • Capped weight value
  • In general, not recommended
  • LLIC = LPAR Licensed Internal Code
  • LP = Logical Partition
intelligent resource director
Intelligent Resource Director
  • IRD brings four new functions to the parallel SYSPLEX that help insure important workloads meet their goals
    • WLM LPAR Weight Management
    • WLM Vary CPU Management
    • Dynamic Channel-Path Management
    • Channel Subsystem I/O Priority Queueing
ird pr sm wlm
IRD = PR/SM + WLM
  • IRD WLM CPU management allows WLM to dynamically change the weights and number of online logical CPs of all z/OS shared LPs in a CPC LPAR cluster
  • IRD WLM Weight Management
    • Allows WLM to instruct PR/SM to adjust shared LP weight
  • IRD WLM Vary CPU Management
    • Allows WLM to instruct PR/SM to adjust logical CPs online to LPs
  • LP = Logical Partition
  • Logical CP = Logical Processor
ird prerequisites

HMC Image Profile

ZOS1

IRD Prerequisites
  • Running z/OS in 64-bit mode
  • Running z/900 in LPAR mode
  • Using shared (not dedicated) CPs
  • No hard LP caps
  • Running WLM goal mode
  • LPs must select “WLM Managed”
  • Access to SYSPLEX coupling facility
  • LP = Logical Partition
what is an lpar cluster

dedicated

ZOSX

ZOSD

ZOSY

dedicated

Linux

ZOSZ

z/VM

ZOSA

ZOS1

ZOSB

ZOS2

shared

shared

ZOSC

ZOS3

ZOSD

ZOS4

ZOSE

ZOS5

SYSPLEX1

SYSPLEX2

What is an LPAR Cluster?

An LPAR cluster is the set of all z/OS shared LPs in the same z/OS parallel SYSPLEX on the same CPC

z900

z900

  • CPC = Central Processor Complex
what is an lpar cluster41
What is an LPAR Cluster?

4 LPAR clusters in this configuration (color coded)

z900

z900

dedicated

ZOSX

ZOSD

ZOSY

dedicated

Linux

ZOSZ

z/VM

ZOSA

ZOS1

ZOSB

ZOS2

shared

shared

ZOSC

ZOS3

ZOSD

ZOS4

ZOSE

ZOS5

SYSPLEX1

SYSPLEX2

wlm lpar weight management
WLM LPAR Weight Management
  • Dynamically changes LP Weights
  • Donor Receiver Strategy
  • WLM Evaluates all SYSPLEX Workloads
  • Suffering Service Class Periods (SSCPs)
    • High (>1) SYSPLEX Performance Index (PI)
    • High Importance
    • CPU delays
  • LP = Logical Partition
  • WLM = Workload Manager
wlm policy adjustment cycle
WLM Policy Adjustment Cycle
  • IF The SSCP is missing goal due to CPU Delay
  • and WLM cannot help the SSCP by adjusting
  • dispatch priorities within an LP
  • THEN WLM and PR/SM start talking ---
  • Estimate impact of increasing SSCPs LP weight
  • Find donor LP if there will be SSCP PI improvement,
  • Donor LP must contain heavy CPU using SCP
  • Evaluate impact of reducing donor LPs weight
  • - Cannot hurt donor SCPs with >= importance
  • WLM changes weights via new LPAR interface
  • WLM = Workload Manager

SSCP = Suffering Service Class Periods

PI = Performance Index

SCP = Service Class Period

rules and guidelines
Rules and Guidelines
  • 5% from donor, 5% to receiver
  • No “recent” LP cluster weight adjustments
    • Must allow time for impact of recent adjustments. Avoid see-saw effect
  • Receiver and Donor LPs will always obey specified min/max weight assignments
  • Non-z/OS images unaffected because total shared LP weight remains constant!
  • LP = Logical Partition
goals should reflect reality
Goals Should Reflect Reality

MAKE SURE YOUR SCP GOALS AND IMPORTANCE REFLECT REALITY AT THE LPAR CLUSTER LEVEL!

Because WLM thinks you knew what you were doing!

SCP = Service Class Period

  • WLM = Workload Manager
goals reality continued
Goals / Reality Continued
  • In the past, the WLM goal mode SCPs on your “test” or “development” LPs had no impact on “production” LPs
    • If part of the same LPAR cluster,
    • IRD will take resource away (decrease weight) of “production” LP,
    • Add resource (increase weight) of “test” LP to meet the goal set for a SCP of higher importance on “test” LP
  • Develop service policy as though all SCPs are running on a single system image
  • WLM = Workload Manager

SCP = Service Class Period

  • LP = Logical Partition
workload manager level of importance
Workload Manager Level of Importance
  • WLM uses the Level of Importance YOU assign to make resource allocation decisions!

CICS WEBSITE DAVE’S STUFF

Importance 1

Importance 2

Importance 3

Importance 4

GUTTER WORK BOB’S STUFF

Importance 5

wlm vary cpu management
WLM Vary CPU Management
  • Varies logical CPs online/offline to LPs
  • Goals:
    • Higher effective logical CP speed
    • Less LPAR overhead and switching
  • Characteristics:
    • Aggressive: Vary logical CP online
    • Conservative: Vary logical CP offline
  • Influenced by IRD LP weight adjustments
  • LP = Logical Partition
  • Logical CP = Logical Processor
vary cpu algorithm parameters
Vary CPU Algorithm Parameters
  • Only initially online logical CPs eligible
    • Operator varied offline not available
  • If z/OS LP switched to compatibility mode,
    • all IRD weight and vary logical CP adjustments “undone”.
    • LP reverts to initial CP and weight settings
  • CP = Central Processor
  • LP = Logical Partition
  • Logical CP = Logical Processor
what is online time

LCP

LCP

LCP

What is Online Time?

RMF interval: 30 minutes

ZOS2

PRESENT (IRD)

PAST (pre-IRD)

---------- 30 MINUTES ----------

---------- 30 MINUTES ----------

LCP 0

LCP 0

LCP 1

LCP 1

LCP 2

LCP 2

Note: LCP 2 varied offline during interval

Interval time=online time

LPC Dispatch Time

In the past, RMF only indicated that LPC 2 was not online at end of interval. Now, RMF reports the online time for each LPC for each partition.

Previously, the length of the interval was the MAX time that each LCP could be dispatched. RMF reports on the actual dispatch time.

vary cpu cpu percent busy
Vary CPU - CPU Percent Busy
  • Before IRD CPU Vary Management

CPU Time = Interval Time - Wait Time

and CPU % Busy = CPU Time * 100

Interval Time * No. Processors

  • After IRD CPU Vary Management

CPU Time = Online Time - Wait Time

and CPU % Busy = CPU Time * 100

Total Online Time

  • New SMF70ONT field, total time processor online to LP during RMF interval
dynamic channel path management dcm
Dynamic Channel-PathManagement (DCM)
  • Goals
    • Better I/O response (less pend) time
    • I/O configuration definition simplification
    • Reduces the need for > 256 channels
    • Enhanced availability
    • Reduced management
  • Operates in both goal and compatibility modes
dcm prerequisites
DCM Prerequisites
  • Systems running on z900 or later CPC
  • Running z/OS 1.1 in 64 bit mode
  • Both LPAR and Basic mode supported
  • To share managed channels on same CPC
    • Systems in LPAR cluster
  • Balance mode either compatibility or goal
  • Goal mode requires WLM goal mode and that global I/O Priority queuing selected
  • CPC = Central Processor Complex
  • DCM = Dynamic Channel-path Management
ird dcm balance mode
IRD DCM Balance Mode

Before IRD DCM

After IRD DCM

PCT

Busy

PCT

Busy

Channel Path

Channel Path

Stated simply, the goal of IRD DCM is to evenly distribute

I/O activity across all channel paths attached to the CPC

  • CPC = Central Processor Complex
  • DCM = Dynamic Channel-path Management
dcm balance mode
DCM Balance Mode
  • Moves channel bandwidth where needed
  • Simplified configuration definition
    • For managed CUs, define 2 non-managed paths plus n managed paths to meet peak workload
  • DCM balanced mode removes paths from non-busy CUs and adds paths to busy CUs
  • Currently manages paths to DASD CUs
  • New metric: I/O Velocity
  • CU = Control Unit
  • DCM = Dynamic Channel-path Management
i o velocity
I/O Velocity

I/O Velocity =

LCU productive time

LCU productive time + channel contention delays

  • Calculated by WLM and the IOS
  • Uses the same CF structure for CPU mgmt
  • Calculated for every LCU in LPAR cluster to compute a weighted average
  • DCM attempts to ensure all managed LCUs have similar I/O velocities
  • DCM = Dynamic Channel Path Management
  • CF = Coupling Facility
  • LCU = Logical Control Unit
dcm goal mode
DCM Goal Mode
  • All LPs in I/O cluster in WLM goal mode
  • During policy adjustment routine WLM selects SSCP
    • IF I/O delays the problem&increasing I/O priority does not help&adding alias for PAV volumes will not help&I/O requests suffering channel contention …
    • THEN WLM estimates impact of increasing LCU I/O velocity and if benefits SCP PI, sets explicit velocity for LCU
  • Explicit velocity overrides Balance mode

SCP = Service Class Period

PI = Performance Index

SSCP = Suffering Service Class Periods

  • LCU = Logical Control Unit
channel subsystem css i o priority queueing
Channel Subsystem (CSS)I/O Priority Queueing
  • Dynamically manages channel subsystem I/O priority against WLM policy goals
  • Only meaningful when I/Os are queued
  • Supports prioritization of:
    • I/Os waiting for a SAP
    • I/Os waiting for a channel
  • Previously, these delays were handled FIFO

SAP = System Assist Processor

channel subsystem i o priority queueing cont d
Channel Subsystem I/O Priority Queueing (cont’d)
  • Uses Donor Receiver strategy
  • CSS I/O priority setting (waiting for a SAP)
    • System SCP assigned highest priority
    • I/O delayed SCP missing goal next
    • When meeting goals:
      • Light I/O users higher
      • Discretionary work has lowest priority
  • UCB and CU I/O priority setting (waiting for a channel)
    • System SCP assigned highest priority
    • I/O delayed SCP missing goal next
    • Less important SCP is donor

SAP = System Assist Processor

SCP = Service Class Period

ibm license manager ilm
IBM License Manager (ILM)
  • PROBLEMS:
    • Software charges based on CPC size
    • CPCs getting bigger
    • Workloads more erratic (spikes)
      • eBusiness
  • SOLUTION
    • New LP setup option: Defined Capacity
    • Software priced at LP Defined Capacity
  • CPC = Central Processor Complex
  • LP = Logical Partition
ibm license manager ilm61
IBM License Manager (ILM)
  • z/900 servers running z/OS V1R1+
  • New external: “Defined Capacity” for shared LPs
  • Defined capacity expressed in MSUs
    • Millions of Service Units per hour
  • Rolling 4 hour average MSU use compared with defined capacity by WLM
  • When rolling 4 hour MSU usage exceeds defined capacity, WLM tells PR/SM to “soft cap” LP (really a temporary hard cap)
  • LP = Logical Partition
  • MSU = Millions of Service Units
rolling four hour average
Rolling Four Hour Average

Actual MSUs Consumed

Average Actual

Avg Rolling

Rolling Avg Detail

ibm license manager ilm63
IBM License Manager (ILM)
  • For software pricing, IBM uses following:
    • Dedicated LPs - logical CPs * engine MSU
    • PR/SM hard cap - shared pool % * engine MSU
    • Defined Capacity - defined capacity
    • Basic mode - model’s MSU rating
  • www.ibm.com/servers/eserver/zseries/srm/
  • Logical CP = Logical Processor
  • MSU = Millions of Service Units
ibm license manager ilm64
IBM License Manager (ILM)

If ZOS1 set with defined capacity of 100 MSU …

175

White Space

Ability to handle spikes and unpredictable demand

100

Defined Capacity

capacity upgrade on demand

ICF = Integrated Coupling Facility

  • CP = Central Processor
  • CUoD = Capacity Upgrade on Demand

PU = Processor Unit

Capacity Upgrade on Demand
  • CUoD supports non-disruptive activation of PUs as CPs or ICFs in a CPC
  • Specify “Reserved Processors”
  • When an upgrade is made (105 to 106)
    • LPs with reserved processors can begin using immediately after operator command
  • IBM recommends specifying as many reserved processors as model supports
  • CPC = Central Processor Complex
  • LP = Logical Partition
z900 model 2064 10566

PU

PU

PU

PU

CP

CP

CP

PU

SAP

SAP

CP

CP

All contain a 12 PU MultiChip Module (MCM)

CPC MEMORY

CP

Central (General) Processor

z900 Model 2064-105

5 PUs Configured as CPs = Model 105

CPs Defined = Model Number

shared lps67
Shared LPs

HMC Image Profile

ZOS1

z900 model 2064 106

PU

PU

PU

CP

CP

CP

CP

PU

SAP

SAP

CP

CP

CPC MEMORY

CP

Central (General) Processor

z900 Model 2064-106

All contain a 12 PU MultiChip Module (MCM)

5 +1 PUs Configured as CPs = Model 106

CPs Defined = Model Number

lp weights lp weight

LCP

CP

L

LCP

LCP

LCP

LCP

L

L

LCP

L

L

CP

LCP

CP

CP

CP

CP

Shared CP Pool

LCP

LP Weights - LP Weight %

PR/SM LPAR LIC

CPC MEMORY

ZOS1

ZOS2

400

100

ZOS1 Image

ZOS2 Image

  • Total of LP Weights = 400 + 100 = 500
  • ZOS1 LP Weight % = 100 * 400/500 = 80%
  • ZOS2 LP Weight % = 100 * 100/500 = 20%
lp target cps70

ZOS1

ZOS2

CP

CP

CP

CP

CP

LCP

LCP

LCP

CP

L

L

L

L

L

LCP

LCP

LCP

LCP

Shared CP Pool

LCP

LP Target CPs

PR/SM LPAR LIC

CPC MEMORY

400

100

ZOS1 Image

ZOS2 Image

  • ZOS1 Weight % = 80%
  • Target CPs = 0.8 *6 = 4.8 CPs
  • ZOS2 LP Weight % = 20%
  • Target CPs = 0.2 * 6 = 1.2 CPs
lp logical cp share71
LP Logical CP share
  • ZOS1 LP is guaranteed 4.8 physical CPs
    • ZOS1 can dispatch work to 5 logical CPs
    • Each ZOS1 logical CP gets 4.8/5 or 0.96 CP
    • ZOS1 effective speed = 0.96 potential speed
  • ZOS2 LP is guaranteed 1.2 physical CP
    • ZOS2 can dispatch work to 3 logical CPs
    • Each ZOS2 logical CP gets 1.2/3 or 0.40 CP
    • ZOS2 effective speed = 0.40 potential speed
  • CP = Central Processor
  • Logical CP = Logical Processor
conclusions
Conclusions
  • Large system resource, configuration, and workload management tasks shifting towards intelligent, automated, dynamic WLM functions
  • Responsibility of capacity planners and performance analysts shifting towards better understanding of business workloads relative importance and performance requirements
neumics support
NeuMICS Support
  • April 2002 PSP
      • CAP - New IRD and ILM Planning Applications
      • PER - New MSU and Soft Capping Analysis
  • October 2001 PSP
      • RMF6580 - IRD, ILM, and CUoD
  • April 2001 PSP
      • RMF6560 - z/OS (64 bit) Multisystem Enclaves, USS Kernal, and 2105 Cache Controllers
  • October 2000 PSP
      • RMF6540 - ICF, IFL, and PAV support
references
References
  • Parallel Sysplex Overview: Introducing Data Sharing and Parallelism in a Sysplex (SA22-7661-00)
  • Redbook: z/OS Intelligent Resource Director (SG24-5952-00)
  • IBM e-server zSeries 900 and z/OS Reference Guide (G326-3092-00)
  • zSeries 900 Processor Resource/Systems Manger Planning Guide (SB10-7033-00)
trademarks
PR/SM

RMF

SMF

Sysplex Timer

S/390

VSE/ESA

zSeries

z/OS

CICSDB2

ESCON

FICON

IBM

IMS

MVS

MVS/ESA

OS/390

Parallel Sysplex

Processor Resource/Systems Manager

Trademarks

The following terms are trademarks of the International Business Machines Corporation in the United States, or other countries, or both:

thanks
Thanks!

Questions ???

Darrell Faulkner

NeuMICS Development Manager

Computer Associates

Email: darrell.faulkner@ca.com