sysmgr_runstate(), sysmgr_runstate_dynamic()

Change the runstate of a processor

Synopsis:

#include <sys/sysmgr.h>

int sysmgr_runstate( unsigned cpu,
                     int enable );

int sysmgr_runstate_dynamic( unsigned cpu,
                             int enable );

Arguments:

cpu
The index of the CPU whose state you want to change.
enable
0 to turn the processor off; non-zero to turn it on. For more details, see below.

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Description:

The sysmgr_runstate() and sysmgr_runstate_dynamic() functions turn the specified CPU on or off as follows:

  • sysmgr_runstate() takes a CPU down manually (if enable is zero) or lets it run (if one).
  • sysmgr_runstate_dynamic() lets the kernel dynamically bring a CPU up or down (if enable is one), depending on the system load.

These settings work together:

Runstate Dynamic runstate Action
0 — The CPU is permanently off
1 0 The CPU is permanently on (the default)
1 1 The CPU is dynamically brought up or down by the kernel, depending on load.
In order to successfully change the state, your process must have the PROCMGR_AID_RUNSTATE ability enabled. For more information, see procmgr_ability() .

Errors:

EINVAL
The CPU index is invalid.
EOK
Success.
EPERM
The calling process doesn't have the required permission; see procmgr_ability() .

Classification:

QNX Neutrino

Safety:
Cancellation point No
Interrupt handler No
Signal handler Yes
Thread Yes

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