rtsched.2 (2010 09)

r
rtsched(2) rtsched(2)
described and the strongest priority in the priority range for
SCHED_OTHER is
weaker than the weakest priority in the priority ranges for any of the other policies,
SCHED_FIFO, SCHED_RR, and SCHED_RR2.
SCHED_NOAGE A timeshare scheduling policy with nondecaying priorities.
For processes executing under this policy, the implementation can use only priori-
ties within the range returned by the functions
sched_get_priority_max()
and sched_get_priority_min()
when SCHED_NOAGE is provided as the
parameter. The priority range for the
SCHED_NOAGE policy is a subset of the
priority range supported by the SCHED_TIMESHARE
policy. Note that for the
SCHED_NOAGE scheduling policy, smaller numbers represent higher (stronger)
priorities, which is the opposite of the POSIX scheduling policies.
The priority value of a thread executing with the
SCHED_NOAGE policy is not
decayed or boosted by the operating system scheduler. For
SCHED_TIMESHARE
policy, the priority value of the thread is decayed as the thread consumes processor
cycles and boosted when the thread waits for processor cycles.
The threads in different processor sets do not compete with one another for processors based on their
scheduling policy and priority values. The scheduler looks only at threads assigned to a processor’s pro-
cessor set to choose the next thread to run. A process with lower scheduling priority in one processor set
may be executing while another process in another processor set with higher scheduling priority is wait-
ing for the processor resources. This is applicable for all scheduling policies.
Security Restrictions
Some or all of the actions associated with this system call are subject to compartmental restrictions. See
compartments (5) for more information about compartmentalization on systems that support that feature.
Compartmental restrictions can be overridden if the process possesses the
COMMALLOWED privilege
(
PRIV_COMMALLOWED
). Processes owned by the superuser may not have this privilege. Processes
owned by any user may have this privilege, depending on system configuration.
Some or all of the actions associated with this system call require the
OWNER or the RTSCHED
privilege.
Processes owned by the superuser have these privileges. Processes owned by other users may have these
privileges, depending on system configuration. See privileges (5) for more information about privileged
access on systems that support fine-grained privileges.
RETURN VALUE
The functions return the following values:
sched_getparam(), sched_rr_get_interval(), sched_setparam(), sched_yield()
0 Successful completion.
-1 Failure. errno is set to indicate the error.
sched_setscheduler()
n Successful completion. n is the former scheduling policy of the specified process.
-1 Failure. The policy and scheduling parameters remain unchanged. errno is set to indicate
the error.
sched_getscheduler()
n Successful completion. n is the scheduling policy of the specified process.
-1 Failure. errno is set to indicate the error.
sched_get_priority_max(), sched_get_priority_min()
n Successful completion. n is the maximum or minimum value, respectively.
-1 Failure. errno is set to indicate the error.
PRI_HPUX_TO_POSIX()
n Successful completion. n is the POSIX.4 priority corresponding to pri.
PRI_POSIX_TO_HPUX()
n Successful completion. n is the the HP-UX priority corresponding to pri .
6 Hewlett-Packard Company − 6 − HP-UX 11i Version 3: September 2010