mpctl.2 (2010 09)

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mpctl(2) mpctl(2)

If the processor set binding for a process or an LWP in a launch tree is changed to another processor set,

that process or LWP becomes the root of a new launch tree. When creating a new process or an LWP, if

the root of the launch tree is found to be in a different processor set, the new process or LWP is made the

root of a new launch tree.

NOTE: locality domains are tightly tied to the physical components of the underlying system. As a

result, the performance observed when using launch policies based on locality domains may vary from

system to system. For example, a system which contains 4 locality domains, each containing 32 proces-

sors, may exhibit different performance behaviors from a system that contains 32 locality domains with 4

processors per domain. The launch policy that provides optimal performance on one system may not pro-

vide optimal performance on a different system for the same application.

For process launch policies use:

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

The request argument determines the precise action to be taken by

mpctl() and is one of the following:

MPC_GETPROCESS_LAUNCH

This request currently returns

MPC_LAUNCH_POLICY_RR

MPC_LAUNCH_POLICY_FILL

, MPC_LAUNCH_POLICY_PACKED

MPC_LAUNCH_POLICY_LEASTLOAD

, MPC_LAUNCH_POLICY_RR_TREE

MPC_LAUNCH_POLICY_FILL_TREE

,orMPC_LAUNCH_POLICY_NONE

indicate the current launch policy of the process speciﬁed by pid. Other launch

policies may be added in future releases and returned via this option. Applica-

tions using this option should be written to handle other return values in order

to continue working on future releases. The ldom argument is ignored.

MPC_SETPROCESS_RR

This call establishes a round robin launch policy (MPC_LAUNCH_POLICY_RR

)

for the speciﬁed process. The successive child processes are launched on

different locality domains in a round robin manner until all available locality

domains have been used by processes in the launch tree. At that point, the

selection of locality domains begins again from the original locality domain. The

ldom argument is ignored.

MPC_SETPROCESS_FILL

This call establishes a ﬁll ﬁrst launch policy (MPC_LAUNCH_POLICY_FILL

) for

the speciﬁed process. The successive child processes are launched on the same

locality domain as their parent process until one process has been created for

each available processor in the domain. At that point, a new locality domain is

selected and successive processes are launched there until there is one process

per processor. All available locality domains will be used before the original

domain is selected again. The ldom argument is ignored.

MPC_SETPROCESS_PACKED

This call establishes a packed launch policy (MPC_LAUNCH_POLICY_PACKED)

for the speciﬁed process. The successive child processes are launched on the

same locality domain as their parent process. The ldom argument is ignored.

MPC_SETPROCESS_LEASTLOAD

This call establishes a least loaded launch policy

(MPC_LAUNCH_POLICY_LEASTLOAD) for the speciﬁed process. The successive

child processes are launched on the least loaded locality domain in the processor

set regardless of the location of their parent process. The ldom argument is

ignored.

MPC_SETPROCESS_RR_TREE

This call establishes a tree based round robin launch policy

(MPC_LAUNCH_POLICY_RR_TREE) for the speciﬁed process. This request

differs from MPC_SETPROCESS_RR in which processes become part of the

launch tree. This launch policy includes all descendents of the target process in

the launch tree. The ldom argument is ignored.

MPC_SETPROCESS_FILL_TREE

This call establishes a tree based ﬁll ﬁrst launch policy

(MPC_LAUNCH_POLICY_FILL_TREE) for the speciﬁed process. This request

differs from MPC_SETPROCESS_FILL in which processes become part of the

10 Hewlett-Packard Company − 10 − HP-UX 11i Version 3: September 2010