gtpm2m0mMigration Guide: Program Update Tapes

Shared PR/SM (APAR PJ17778)

The following section discusses the migration considerations for shared PR/SM.

Prerequisite APARs

See the APEDIT for APAR PJ17778 for information about prerequisite APARs.

After applying shared PR/SM support and all prerequisite APARs in the data collection and reduction areas, the link-edited data reduction program will not successfully process data collection tapes created on a TPF 4.1 system at the PUT 2 level. If your complex has a requirement to continue running data reduction for such tapes, you must maintain a separate data reduction program.

Functional Overview

Shared PR/SM support allows tightly coupled TPF systems to run in shared PR/SM partitions. This support offers the following advantages:

Architecture

Shared PR/SM support is implemented by allowing logical CPUs in a shared PR/SM partition to load enabled wait-state PSWs when no work is available for the associated I-stream. When another I-stream places work on the cross list of the waiting I-stream, a SIGP instruction is executed, causing an external-call external interrupt condition to be generated for the CPU associated with the waiting I-stream. This external interrupt causes PR/SM to dispatch the logical CPU as soon as a physical CPU is available, thereby eliminating excessive wait times. Similar processing is performed when a CPU loads an enabled wait-state PSW during DEFRC or DLAYC macro processing.

Calculation of CPU utilization is enhanced by obtaining CPU utilization statistics directly from the shared PR/SM facility rather than using TPF-based logic that is unaware of the higher-level dispatching activity controlled by the shared PR/SM facility.

Operating Environment Requirements and Planning Information

There are none.

Interface Changes

The following section summarizes interface changes.

C/C++ Language

The following section summarizes C/C++ language changes. This information is presented in alphabetic order by the type of C/C++ language information. See the TPF C/C++ Language Support User's Guide and TPF Application Programming for more information about C/C++ language.

Build Scripts

There are no changes.

Dynamic Load Module (DLM) Stubs

There are no changes.

General Use C Language Header Files

Table 42 summarizes the general use C language header file changes. This information is presented in alphabetic order by the name of the general use C language header file.

General use means these header files are available for your use.

Table 42. Changes to General Use C Language Header Files for Shared PR/SM

General Use C Language Header File New, Changed, or No Longer Supported? Do You Need to Recompile Segments?
c$dctist.h Changed No
c$systc.h Changed No

Implementation-Specific C/C++ Language Header Files (IBM Use Only)

There are no changes.

Library Interface Scripts

There are no changes.

Library Members (Object Files)

There are no changes.

Link-Edited Modules

There are no changes.

Members (Object Files)

There are no changes

Object Code Only (OCO) Stubs

There are no changes.

Configuration Constant (CONKC) Tags

There are no changes.

Control Program Interface (CINFC) Tags

There are no changes.

Copy Members

Table 43 summarizes copy member changes. This information is presented in alphabetic order by the name of the copy member.

Table 43. Changes to Copy Members for Shared PR/SM

Copy Member Type CSECT Where Copy Member Is Located New, Changed, or No Longer Supported? Description of Change
CCE7 Control Program CCIISC Changed Modified the CPU utilization calculation for CPUs in a PR/SM environment.
CICR Control Program CCNUCL Changed Modified the conditions under which DEFRC and DLAYC macro service routines cause an enabled wait-state PSW to be loaded.
CLHL Control Program CCCLHR Changed Modified the $CRISC service routine to execute a $CPUC macro if the target I-stream is waiting; modified the conditions under which both the main and application CPU loops cause an enabled wait-state PSW to be loaded.
CPSE Control Program CCCPSE Changed Modified the Perch routines to set up the ECRC before issuing a $CPUC macro.
CTME Control Program CCNUCL Changed Modified the external interrupt handler to identify the reason for an external-call external interrupt and pass control to the appropriate routine.
CT38 Control Program CCCTIN Changed Allocate storage for information returned by the DIAG X'204' instruction.

Fixed File Records

There are no changes.

Macros

The following section summarizes the macro changes. This information is presented in alphabetic order by the type of macro.

Advanced Program-to-Program Communications (APPC) Macros

There are no changes.

Communication Macros and Statements

There are no changes.

Data Macros

Table 44 summarizes the data macro changes. This information is presented in alphabetic order by the name of the data macro.

Table 44. Changes to Data Macros for Shared PR/SM

Data Macro New, Changed, or No Longer Supported? Do You Need to Reassemble Programs Using This Data Macro?
DCTIST Changed No
IB0CT Changed No

General Macros

There are no changes.

Selected Equate Macros

There are no changes.

Structured Programming Macros (SPMs)

There are no changes.

System Initialization Program (SIP) Skeleton and Internal Macros (Inner Macros)

There are no changes.

System Initialization Program (SIP) Stage I Macros and Statements

There are no changes.

System Initialization Program (SIP) Stage II Macros

There are no changes.

System Communication Keypoint (SCK) Generation Macros

There are no changes.

System Macros

Table 45 summarizes system macro changes. This information is presented in alphabetic order by the name of the system macro. See TPF System Macros for a complete description of all system macros.

Table 45. Changes to System Macros for Shared PR/SM

System Macro New, Changed, or No Longer Supported? Do You Need to Reassemble Programs?
$LOCKC Changed No

System Macros (IBM Use Only)

There are no changes.

Segments

Table 46 summarizes segment changes. This information is presented in alphabetic order by the name of the segment.

Table 46. Changes to Segments for Shared PR/SM

Segment Type New, Changed, or No Longer Supported? Description of Change
JCD4 Real-Time Assembler Changed Modified to collect information about the operating environment.
JRA1 Offline PL/I Changed Include the operating environment in the Environment Summary report.
JRA3 Offline PL/I Changed Redefine the data created by data collection to include operating environment information.

System Equates

There are no changes.

User Exits

There are no changes.

Functional and Operational Changes

There are no changes.

Performance or Tuning Changes

The following performance and tuning recommendations are made for TPF systems running in shared PR/SM partitions.

Item
Recommendation

 Logical CPUs 
Define a shared PR/SM partition with the minimum number of logical CPUs to satisfy the peak demands of the TPF system running in that partition. An excessive number of CPUs results in associated hardware performance penalties.

 Processor Run Time 
The processor run time is the maximum continuous amount of time that a logical CPU is assigned to a physical CPU. All shared PR/SM partitions are assigned the same processor run time. For TPF systems running in a shared PR/SM partition, the recommended processor run time is 5-10ms. A processor run time of less than 5ms can cause loss of throughput, while a processor run time of greater than 10ms can cause excessive response time.

 Wait Completion 
The wait completion setting controls whether a new logical CPU is assigned to a physical CPU when the logical CPU currently assigned to the physical CPU loads an enabled wait-state PSW. For TPF systems running in a shared PR/SM partition, a wait completion setting of NO is recommended. A wait completion setting of YES can cause a significant increase in response time.

 Processor Weights 
The processor weights designate the proportion of the total CPC processor resources (excluding the dedicated processors) to which a shared PR/SM partition is entitled. The processor weights affect processing only when the number of logical processors that need processing time is greater than the number of physical processors available. Set the processor weights to give priority to the partitions running TPF systems.
Note:
For capacity planning, it should be noted that a low-utilization effect is more apparent in shared PR/SM environments than in dedicated PR/SM environments. A low utilization effect causes a slight decrease in throughput at low CPU utilization levels.

Storage Considerations and Changes

There are no changes.

System Initialization Program (SIP) and System Generation Changes

There are no changes.

Loading Process Changes

There are no changes.

Online System Load Changes

There are no changes.

Publication Changes

Table 47 summarizes changes to the publications in the TPF library. This information is presented in alphabetic order by the publication title. See the TPF Library Guide for more information about the TPF library.

Table 47. Changes to TPF Publications for Shared PR/SM

Publication Title Softcopy File Name Description of Change
Messages (System Error and Offline) and Messages (Online) Not Applicable Updated with information about the messages and system errors that were added, changed, and no longer supported for shared PR/SM.
TPF Migration Guide: Program Update Tapes GTPMIG02 Updated with migration considerations for shared PR/SM.
TPF System Performance and Measurement Reference GTPSPR02 Updated by shared PR/SM.

Host System Changes

There are no changes.

Application Programming Interface (API) Changes

There are no changes.

Database Changes

There are no changes.

Feature Changes

There are no changes.

Installation Validation

There are no changes.

Migration Scenarios

There are no migration scenarios.