Chapter13 Shared Pool

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Chapter 13

Subsystems

Understanding AS/400 System Operations 2

Basic Facts All work is carried out

in a subsystem. All jobs are divided by

type into subsystems. Subsystems are

started when the AS/400 powers up and loads the Operating System.

A way of organizing, in order to increase efficiency.

J

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B

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OFFICE


Memory: Activity Levels

Activity levels -enhance raw memory allocation by restricting how many programs will vie for the same memory at the same time.


Why limit activity level? Each job secures enough resources

to run efficiently Too large of a number will force

jobs to compete for system resources and ultimately slow completion of all jobs


Memory: Storage Pools

A storage pool is a pool of memory where one type of program or application (a set of programs) runs.


Subsystems Are: A subsystem is an environment

unique to a type of program. It allows computer run-time attributes to be applied to all jobs within it, while other jobs in other subsystems keep their own attributes.


Single Vs. Multiple Subsystem Configuration

Single - QBASE The subsystem for

all work active upon installation

Convenient for installation

Doesn’t take advantage of system’s capabilities

Multiple Improves performance

to separate workload AS/400 comes

preloaded with basic 5 subsystems

Change system value for QCTLSBSD to QCTL & the AS/400 understands to start using multiple subsystems


5 Basic Subsystems QCTL

the controlling subsystem in a multiple subsystem configuration

The system console is attached to this subsystem

This is so the system console can carry out functions during IPL


5 Basic Subsystems (cont.) QINTER

Subsystem that supports interactive jobs

QSPL Handles all spooled file jobs


5 Basic Subsystems (cont.) QCMN

Supports all communications jobs QBATCH

Supports all batch jobs


5 Basic Subsystems (cont.) The AS/400 allows for any

combination of jobs within a subsystem. However, doing so will reduce the system’s efficiency.

The object, subsystem description, is required whenever a new subsystem is created.


System Pools Also called a storage pool. A logical division of main memory

reserved for processing jobs. Subsystems are pre-assigned to

main memory pools by the Operating System.

Work is divided into types of jobs (Just like types of pools).


Storage Pool Characteristics Activity Level

Max number of jobs that can be run simultaneously in the poolHow many lanes

Pre-defined size number of bytes

that can be stored in the pool How much water


Shipped Storage Pools *MACHINE is the storage pool

where the system runs. *BASE can be where everything

else runs.


Related System Values QMCHPOOL - Sets Size OF

*Machine pool. QBASPOOL - Sets minimum size of

*BASE pool.


Portion of Memory

A pool is the amount of allocated memory.


Memory Management Concepts Paging is writing a inactive

memory page to DASD so an active page can be read into memory.

Faulting is when a program (or its data) attempts to access a page not in memory. It then is fetched.


Memory Management Concepts Timeslice, is the period of

time allocated for CPU usage by a job when it executes.

Thrashing is excessive faulting.


CPU Considerations Time Slices

The amount of processor time a job has before the CPU moves to another job

Run Priorities Within a storage pool, job with highest

prior acquires system resources first Ex: Print writers, then interactive jobs,

then batch jobs


CPU Considerations (cont.) Run Priority Vs. Job Priority

Run priority is the priority of job while executing

Job priority is the relative order of job waiting on job queue


AS/400 Jobs Three States Active—The job is running. Job is

occupying storage, using processor, and hasn’t exceeded activity level.

Wait—The job is waiting for something to happen. Waiting until next user request to start.

Ineligible— The job is ready to run, but the system is not available. Ineligible job can’t occupy storage or processor due to activity level is at max.


AS/400 Jobs Three States (cont.) Jobs shift between states

automatically, depending on system’s work load

Job may need to become ineligible at end of its time slice


Memory Pool Types Shared Pools

Special shared pools. The two pools that come with the AS/400, *MACHINE and *BASE, are special shared pools. These are the only special shared pools.

General shared pools. Private Pools

Maximum pools = 64 including *BASE and *MACHINE.


Pre-defined Pools The AS/400 comes with predetermined

names and, in two cases, predetermined uses, for shared pools.

Here is the list: *INTERACT —Supports interactive

subsystems’ jobs. *SPOOL—Supports spool writers (printing). *SHRPOOL1 through *SHRPOOL60— Names

available for customer-defined shared pools.


Creating Private Pools/ Assigning Shared Pools

Create Subsystem Description (CRTSBSD) Type choices, press Enter. Subsystem description . . . . . _______ Name Library . . . . . . . . . . . *CURLIB Name, *CURLIB Storage pools: ___ Pool identifier . . . . . . . _________ 1-10 Storage size . . . . . . . . . _________ Number, *BASE, *NOSTG... Activity level . . . . . . . . _______ Number + for more values _________ Maximum jobs . . . . . . . . . . *NOMAX 0-1000, *NOMAX Text 'description' . . . . . . . *BLANK Bottom F3=Exit F4=Prompt F5=Refresh F10=Additional parameters F12=Cancel F13=How to use this display F24=More keys


Changing Pool Memory/ Activity Levels Three commands that change

memory and activity level settings on pools.

They are: Work with System Status (WRKSYSSTS) Change Subsystem Description

(CHGSBSD) Change Shared Pool (CHGSHRPOOL)


Changing Pool Memory/ Activity Levels (cont.) There are also two system values

that affect memory pools and activity levels: Machine Pool (QMCHPOOL) Base Activity Level (QBASACTLVL)


Table 13-1: Memory Activity Level Commands

Pool Name Adjustments to Memory

Adjustments to Activity Level

*MACHINE QMCHPOOL (sv) WRKSYSSTS

—— n/a ——

*BASE —— n/a —— QBASACTLVL (sv) WRKSYSSTS

ALL PRIVATE POOLS

WRKSYSSTS CHGSBSD

WRKSYSSTS CHGSBSD

ALL SHARED POOLS

WRKSYSSTS CHGSHRPOOL

WRKSYSSTS CHGSHRPOOL

(sv) = System Value. Use CHGSYSVAL command to change these.


CHGSHRPOOL command Change Shared Storage Pool (CHGSHRPOOL) Type choices, press Enter. Pool identifier . . . . . . . . __________ *MACHINE, *BASE, *INTERACT... Storage size . . . . . . . . . . *SAME Number, *SAME, *NOSTG Activity level . . . . . . . . . *SAME Number, *SAME Paging option . . . . . . . . . *SAME *SAME, *FIXED, *CALC Text 'description' . . . . . . . *SAME ____________________________________________________________________________ Bottom F3=Exit F4=Prompt F5=Refresh F10=Additional parameters F12=Cancel F13=How to use this display F24=More keys

Figure 13-2: CHGSHRPOOL command


Private Pools Changed Within Subsystems

Change Subsystem Description (CHGSBSD) Type choices, press Enter. Subsystem description . . . . . > QINTER Name Library . . . . . . . . . . . *LIBL Name, *LIBL, *CURLIB Storage pools: __ Pool identifier . . . . . . . *SAME 1-10, *SAME Storage size . . . . . . . . . _________ Number, *BASE, *NOSTG... Activity level . . . . . . . . _________ Number + for more values Maximum jobs . . . . . . . . . . *SAME 0-1000, *SAME, *NOMAX Text 'description' . . . . . . . *SAME ___________________________________________________________________________ Bottom F3=Exit F4=Prompt F5=Refresh F10=Additional parameters F12=Cancel F13=How to use this display F24=More keys

Figure 13-3: CHGSBSD command to change private pool sizes.


Work with Subsystems (WRKSBS)

Work with System Status System: BIGBLUE Type options, press Enter. 4=End subsystem 5=Display subsystem description 8=Work with subsystem jobs Subsystem Pool 1 Subsystem Pool 2 Total -----------Subsystem Pools------------ Opt Subsystem Storage (K) 1 2 3 4 5 6 7 8 9 10 _ QBASE 0 2 3 _ QBATCH 0 2 _ QCMN 0 2 _ QCTL 0 2 _ QINTER 0 2 3 System Pool 3 _ QCOMPILE 0 2 11 System Pool 11 _ QSERVER 0 2 _ QSPL 0 2 4 _ QSYSSBSD 0 2 _ QSYSWRK 0 2 System Pool 2 Bottom Parameters or command ===>_________________________________________________________________ F3=Exit F5=Refresh F11=Display system data F12=Cancel F14=Work with system status


WRKSBS – Display Pool Definitions

Display Pool Definitions

System: BIGBLUE Subsystem description: QCOMPILE Status: ACTIVE Pool Storage Activity ID Size (K) Level 1 *BASE 2 *SHRPOOL2 Shared Pool Names Subsystem Pool Number Bottom Press Enter to continue. F3=Exit F12=Cancel

Figure 13-5: Command WRKSBS, displaying pool definitions.


Work with System Status

Work with System Status BIGBLUE 07/05/99 12:06:24

% CPU used . . . . . . : 63.0 Auxiliary storage: Elapsed time . . . . . : 00:30:01 System ASP . . . . . : 22357 M Jobs in system . . . . : 9789 % system ASP used . : 71.4165 % addresses used: Total . . .. . . . . : 187375 M Permanent . . . . . : 22.313 Current unprotect used: 2854 M Temporary . . . . . : 4.707 Maximum unprotect . : 3222 M Type changes (if allowed), press Enter. System Pool Reserved Max -----DB----- ---Non-DB--- Pool Size (K) Size (K) Active Fault Pages Fault Pages 11 50000 0 4 .0 .3 2.7 .0 System Pool Number Bottom Command ===>___________________________________________________________ F3=Exit F4=Prompt F5=Refresh F9=Retrieve F10=Restart F11=Display transition data F12=Cancel F24=More keys

Figure 13-6: Command WRKSYSSTS, information about system pools.


Work Shared PoolsWork Shared Pools

System: BIGBLUE Main storage size (K) . : 655360

Type changes (if allowed), press Enter.

Defined Max Allocated Pool -Paging Option-- Pool Size (K) Active Size (K) ID Defined Current *MACHINE 90000 +++++ 90000 1 *FIXED *FIXED *BASE 88360 32 88360 2 *FIXED *FIXED *INTERACT 10000 7 10000 8 *FIXED *FIXED *SPOOL 12000 7 12000 3 *FIXED *FIXED *SHRPOOL1 200000 10 200000 4 *CALC *CALC *SHRPOOL2 50000 4 50000 11 *FIXED *FIXED *SHRPOOL3 50000 4 50000 10 *CALC *CALC *SHRPOOL4 40000 10 40000 5 *FIXED *FIXED *SHRPOOL5 70000 7 70000 6 *FIXED *FIXED *SHRPOOL6 0 0 0 *FIXED More... Command ===>____________________________________________________________________ F3=Exit F4=Prompt F5=Refresh F9=Retrieve F11=Display tuning data F12=Cancel

Figure 13-7: Command WRKSHRPOOL.


Subsystem Description Create Subsystem Description (CRTSBSD) Type choices, press Enter. Subsystem description . . . . NEWSBS Name Library . . . . . . . . . . *CURLIB Name, *CURLIB Storage pools: _ Pool identifier . . . . . . 2 1-10 Storage size . . . . . . . . *BASE Number, *BASE, *NOSTG... Activity level . . . . . . . Number + for more values Maximum jobs . . . . . . . . . 4 0-1000, *NOMAX Text 'description' . . . . . . *BLANK ______________________________________________________________________ Additional Parameters Sign-on display file . . . . . *QDSIGNON Name, *QDSIGNON Library . . . . . . . . . . ________ Name, *LIBL, *CURLIB Subsystem library . . . . . . *NONE Name, *NONE More... F3=Exit F4=Prompt F5=Refresh F12=Cancel F13=How to use this display F24=More keys

Figure 13-8: Prompted CRTSBSD command.


Add Storage Pools to Subsystem Specify More Values for Parameter POOLS Type choices, press Enter. Storage pools: Pool identifier . . . . . . > 2 1-10 Storage size . . . . . . . . *BASE Number, *BASE, *NOSTG... Activity level . . . . . . . ________ Number Pool identifier . . . . . . 11 1-10 Storage size . . . . . . . . 50000 Number, *BASE, *NOSTG... Activity level . . . . . . . 4 Number Pool identifier . . . . . . 1-10 Storage size . . . . . . . . Number, *BASE, *NOSTG... Activity level . . . . . . . Number Pool identifier . . . . . . 1-10 Storage size . . . . . . . . Number, *BASE, *NOSTG... Activity level . . . . . . . Number More... F3=Exit F4=Prompt F5=Refresh F12=Cancel F13=How to use this display F24=More keys

Figure 13-9: Adding storage pools to a new subsystem description


Routing Entries Display Job Description System: BIGBLUE Job description: QINTER Library: QGPL Message logging: Level . . . . . . . . . . . . . . . . . . . . : 4 Severity . . . . . . . . . . . . . . . . . . . : 0 Text . . . . . . . . . . . . . . . . . . . . . : *NOLIST Log CL program commands . . . . . . . . . . . . : *NO Accounting code . . . . . . . . . . . . . . . . : *USRPRF Print text . . . . . . . . . . . . . . . . . . . : *SYSVAL Routing data . . . . . . . . . . . . . . . . . . : QCMDI

Figure 13-10: A sample of the routing data for a job description.


Routing Entries (cont.) Display Routing Entries System: BIGBLUE Subsystem description: QINTER Status: ACTIVE Type options, press Enter. 5=Display details Start Opt Seq Nbr Program Library Compare Value Pos _ 10 QCMD QSYS 'QCMDI' 1 _ 20 QCMD QSYS 'QS36MRT' 1 _ 40 QARDRIVE QSYS '525XTEST' 1 _ 700 QCL QSYS 'QCMD38' 1 _ 9999 QCMD QSYS *ANY Bottom F3=Exit F9=Display all detailed descriptions F12=Cancel

Figure 13-11: Routing entries in the subsystem description.


Routing Entries (cont.) Display Routing Entry Detail System: BIGBLUE Subsystem description: QINTER Status: ACTIVE Routing entry sequence number . . . . . . . : 10 Program . . . . . . . . . . . . . . . . . . : QCMD Library . . . . . . . . . . . . . . . . . : QSYS Class . . . . . . . . . . . . . . . . . . . : QPTY35 Library . . . . . . . . . . . . . . . . . : QGPL Maximum active routing steps . . . . . . . : *NOMAX Pool identifier . . . . . . . . . . . . . . : 2 Compare value . . . . . . . . . . . . . . . : 'QCMDI' Compare start position . . . . . . . . . . : 1 Press Enter to continue. F3=Exit F12=Cancel F14=Display previous entry

Figure 13-12: Expanded routing entries in the subsystem description.


Workstation Entries AS/400 workstations are devices

(Interactive Jobs Only) Job Queues Autostart Jobs Communication Jobs Pre-start Jobs


Starting Subsystems Start Subsystem (STRSBS) Type choices, press Enter. Subsystem description . . . Name Library . . . . . . . . . *LIBL Name, *LIBL, *CURLIB Bottom F3=Exit F4=Prompt F5=Refresh F12=Cancel F13=How to use this display F24=More keys

Figure 13-13: Prompted STRSBS command.


Ending Subsystems End Subsystem (ENDSBS) Type choices, press Enter. Subsystem . . . . . . . . . . . > QBATCH Name, *ALL How to end . . . . . . . . . . . *CNTRLD *CNTRLD, *IMMED Delay time, if *CNTRLD . . . . . *NOLIMIT Seconds, *NOLIMIT Bottom F3=Exit F4=Prompt 5=Refresh F10=Additional parameters F12=Cancel F13=How to use this display F24=More keys

Figure 13-14: Prompted ENDSBS command.


Basic Work Management Structure

Chapter13 Shared Pool

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