rtsched.2 (2010 09)

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rtsched(2) rtsched(2)

NAME

rtsched: sched_get_priority_max(), sched_get_priority_min(), sched_getparam(), sched_getscheduler(),

sched_rr_get_interval(), sched_setparam(), sched_setscheduler(), sched_yield(), PRI_HPUX_TO_POSIX(),

PRI_POSIX_TO_HPUX() - real-time scheduling operations

SYNOPSIS

#include <sched.h>

int sched_setparam(

pid_t pid,

const struct sched_param *param

);

int sched_getparam(

pid_t pid,

struct sched_param *param

);

int sched_setscheduler(

pid_t pid,

int policy,

const struct sched_param *param

);

int sched_getscheduler(

pid_t pid

);

int sched_yield();

int sched_get_priority_max(

int policy

);

int sched_get_priority_min(

int policy

);

int sched_rr_get_interval(

pid_t pid,

struct timespec *interval

);

int PRI_POSIX_TO_HPUX(

int pri

);

int PRI_HPUX_TO_POSIX(

int pri

);

DESCRIPTION

Summary

sched_get_priority_max() Get maximum scheduling policy

sched_get_priority_min() Get minimum scheduling policy

sched_getparam() Get scheduling parameters of process

sched_getscheduler() Get scheduling policy of process

sched_rr_get_interval() Get execution time limit for a process

sched_setparam() Set scheduling parameters of process

sched_setscheduler() Set scheduling policy and parameters of process

sched_yield() Requeue current thread in thread list

PRI_HPUX_TO_POSIX() Convert HP-UX priority to POSIX

HP-UX 11i Version 3: September 2010 − 1 − Hewlett-Packard Company 1

Summary of content (8 pages)

PAGE 1
rtsched(2) rtsched(2) NAME rtsched: sched_get_priority_max(), sched_get_priority_min(), sched_getparam(), sched_getscheduler(), sched_rr_get_interval(), sched_setparam(), sched_setscheduler(), sched_yield(), PRI_HPUX_TO_POSIX(), PRI_POSIX_TO_HPUX() - real-time scheduling operations SYNOPSIS #include
PAGE 2
rtsched(2) PRI_POSIX_TO_HPUX() rtsched(2) Convert POSIX priority to HP-UX sched_setparam() The sched_setparam() function sets the scheduling parameters of the process specified by pid to the values specified by the sched_param structure pointed to by param . The value of the sched_priority member in the param structure is any integer within the inclusive priority range for the current scheduling policy of the process specified by pid .
PAGE 3
rtsched(2) rtsched(2) param , respectively. The value of the sched_priority member in the param structure can be any integer within the inclusive priority range for the scheduling policy specified by policy . The possible values for the policy parameter are defined in the header file , and mentioned below. If a process described by pid exists, the scheduling policy and scheduling parameters are set for the process whose process ID is equal to pid .
PAGE 4
rtsched(2) rtsched(2) PRI_HPUX_TO_POSIX(), PRI_POSIX_TO_HPUX() These two functions serve to map (translate) the range of HP-UX priorities into the POSIX.4 model. These translations are necessary because the POSIX.4 standard chose larger numbers to represent stronger priorities and the existing HP-UX behavior, which must be maintained for backward compatibility, uses smaller numbers for stronger priorities. The PRI_HPUX_TO_POSIX() function returns the POSIX.
PAGE 5
rtsched(2) SCHED_RR rtsched(2) Round-robin scheduling policy, with a per-system time slice (time quantum). This policy is identical to the SCHED_FIFO policy with the additional condition that when the implementation detects that a running thread has been executing as a running thread for a time period of length returned by the function sched_rr_get_interval(), or longer, the thread becomes the tail of its thread list, and the head of that thread list is removed and made a running thread.
PAGE 6
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.
PAGE 7
rtsched(2) rtsched(2) ERRORS If the functions fail, errno is set to one of the following values. sched_setparam() [EACCES] The target process could not be accessed due to compartmental restrictions. [EFAULT] The param argument points to an invalid address. [EINVAL] One or more of the requested scheduling parameters is outside the range defined for the scheduling policy of the specified pid . [ENOSYS] The function is not supported by this implementation.
PAGE 8
rtsched(2) rtsched(2) perror("sched_get_priority_max() failed"); exit(1); } param.sched_priority = maxpri; if (sched_setscheduler(getpid(), SCHED_FIFO, ¶m) == -1) { perror("sched_setscheduler() failed"); exit(1); } AUTHOR The sched_*() functions were derived from the proposed IEEE POSIX P1003.4 standard, draft 14. PRI_HPUX_TO_POSIX() and PRI_POSIX_TO_HPUX() were developed by HP. SEE ALSO rtsched(1), rtprio(2), privileges(5). STANDARDS CONFORMANCE sched_get_priority_max(): POSIX.