Change Processor Multitasking Information (QWCCHGPR) API

Required Parameter Group:

Maximum number of secondary threads per processor

Input

Binary(4)

Optional Parameter Group:

Error code

I/O

Char(*)

Default Public Authority: *EXCLUDE

Threadsafe: No

The Change processor multitasking (QWCCHGPR) API can be used to set the maximum number of secondary hardware threads per processor on systems that support simultaneous multithreading. The processor multitasking (QPRCMLTTSK) system value should be set to 1 (on) or 2 (system controlled) when using this API to set the maximum number of secondary processor threads used by the system. This API will have no effect on the number of secondary processor threads used when the processor multitasking (QPRCMLTTSK) system value is 0 (off). To disable all secondary processor threads, use the Change System Value (CHGSYSVAL) command to set QPRCMLTTSK to 0 (off). See the processor multitasking (QPRCMLTTSK) system value for more information on simultaneous multithreading.

Authorities and Locks

This API is shipped with *EXCLUDE public authority.

To use this API you must:

be explicitly authorized to the API, or call the API from a program that adopts enough authority to call the API and have *JOBCTL special authority.

Required Parameter Group

Maximum number of secondary threads per processor

INPUT; BINARY(4)

The maximum number of secondary hardware threads per processor that may be active at the same time when QPRCMLTTSK is on. Possible values are:

0	The system may use the maximum number of processor threads that the hardware supports.
1-255	The system may use up to the specified maximum number of secondary threads per processor. There is always at least one processor thread used per active processor. This value represents the number of additional threads per processor that may be active at the same time.

Optional Parameter Group

Error code: I/O; CHAR(*)
The structure in which to return error information. For the format of the structure, see Error code parameter.

Usage Notes

This API may be called from a command line. Note that the single required parameter, Maximum number of secondary threads per processor, must be entered in hexadecimal format. For example:
CALL PGM(QWCCHGPR) PARM(X'00000001')

Error Messages

Message ID	Error Message Text
CPF222E E	&1 special authority is required.
CPF24B4 E	Severe error while addressing parameter list.
CPF3C36 E	Number of parameters, &1, entered for this API was not valid.
CPF3C3C E	Value for parameter &1 not valid.
CPF3CF1 E	Error code parameter not valid.
CPF3CF2 E	Error(s) occurred during running of &1 API.
CPF9872 E	Program or service program &1 in library &2 ended. Reason code &3.

API introduced: V7R1 by PTF

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