HP-UX Reference (11i v1 05/09) - 2 System Calls (vol 5)

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mpctl(2) mpctl(2)

MPC_SETLWP_FORCE

This call is identical to MPC_SETLWP except that the processor binding will take

precedence over the scheduling policy. This call is synchronous. For example,

when a processor is ready choose another LWP to execute, and the highest priority

SCHED_FIFO LWP is bound to a different processor, that LWP will not be

selected to execute on the selecting processor, but instead wait for the speciﬁed

processor to which it was bound. The selecting processor will then choose a lower

priority LWP to execute on the processor.

Note: This option will not guarantee compliance with POSIX real-time scheduling

algorithms.

For locality domain binding use:

int mpctl(mpc_request_t request, ldom_t ldom, pid_t pid);

int mpctl(mpc_request_t request, ldom_t ldom, lwpid_t lwpid);

The request argument determines the precise action to be taken by

mpctl and is one of the following:

MPC_SETLDOM This request synchronously assigns process pid to locality domain ldom. The pro-

cess may still run on any processor within the locality domain. The new locality

domain assignment is returned.

The pid

MPC_SELFPID may be used to refer to the calling process.

The ldom MPC_LDOMNOCHANGE

may be passed to read the current assignment.

The ldom

MPC_LDOMFLOAT may be used to break any speciﬁc-locality domain

assignment. This allows the process to ﬂoat to any locality domain.

For example, when a processor in one locality domain is ready to choose another

process to execute, and the highest priority

SCHED_FIFO process is bound to a

different locality domain, that process will not be selected to execute on the select-

ing processor, but instead wait for a processor in the speciﬁed locality domain to

which it was bound. The selecting processor will then choose a lower priority pro-

cess to execute on the processor.

Note: This option will not guarantee compliance with POSIX real-time scheduling

algorithms.

If the process speciﬁed by pid is a multithreaded process, all LWPs (lightweight

processes) in the target process with the same processor set binding as the target

process will have their locality domain assignment changed to what is speciﬁed.

The processor set binding takes precedence over processor or locality domain bind-

ing.

MPC_SETLWPLDOM

This request synchronously assigns LWP (lightweight process) lwpid to locality

domain ldom. The LWP may still run on any processor within the locality domain.

The new locality domain assignment is returned. This option is only available to

change the assignment for LWPs in the current process.

The lwpid

MPC_SELFLWPID may be used to refer to the calling LWP.

The ldom MPC_LDOMNOCHANGE may be passed to read the current assignment.

The ldom MPC_LDOMFLOAT may be used to break any speciﬁc-locality domain

assignment. This allows the LWP to ﬂoat to any locality domain.

For example, when a processor is ready to choose another LWP to execute, and the

highest priority SCHED_FIFO LWP is bound to processor in a different locality

domain, that LWP will not be selected to execute on the selecting processor, but

instead wait for a processor on the locality domain to which it was bound. The

selecting processor will then choose a lower priority LWP to execute on the proces-

sor.

Note: This option will not guarantee compliance with POSIX real-time scheduling

algorithms.

HP-UX 11i Version 1: September 2005 − 5 − Hewlett-Packard Company Section 2−−171