HP-UX Reference (11i v2 04/09) - 1 User Commands N-Z (vol 2)

r
rtsched(1) rtsched(1)
NAME
rtsched - execute process with real-time priority
SYNOPSIS
rtsched -s scheduler -p priority command [ arguments ]
rtsched [ -s scheduler ]-ppriority -P pid
DESCRIPTION
Rtsched executes command with POSIX or HP-UX real-time priority, or changes the real-time priority
of currently executing process pid.
All POSIX real-time priority processes are of greater scheduling importance than processes with HP-UX
real-time or HP-UX timeshare priority. All HP-UX real-time priority processes are of greater scheduling
importance than HP-UX timeshare priority processes, but are of lesser importance than POSIX real-time
processes. Neither POSIX nor HP-UX real-time processes are subject to degradation. POSIX real-time
processes may be scheduled with one of three different POSIX real-time schedulers: SCHED_FIFO,
SCHED_RR, or SCHED_RR2. See rtsched (2) for details.
Rtsched is a superset of rtprio. See rtprio (1).
Options
-s scheduler Specify the desired scheduler:
POSIX real-time schedulers: SCHED_FIFO
SCHED_RR
SCHED_RR2
HP-UX real-time scheduler: SCHED_RTPRIO
HP-UX timeshare scheduler: SCHED_HPUX
SCHED_NOAGE
-p priority Specify priority range; any integer within the inclusive priority range of the correspond-
ing scheduler. -p priority is required for all schedulers except SCHED_HPUX. If
scheduler is SCHED_HPUX, the priority argument is ignored. The default priority range
of each scheduler is as follows:
scheduler highest priority lowest priority
SCHED_FIFO 31 0
SCHED_RR 31 0
SCHED_RR2 31 0
SCHED_RTPRIO 0 127
SCHED_NOAGE 178 255
SCHED_HPUX N/A N/A
Note: Higher numerical values for the priority represent higher priorities under POSIX
real-time schedulers, whereas lower numerical values for the priority represent higher
priorities under HP-UX real-time and timeshare schedulers.
-P Specify an already executing process ID (pid).
Command is not scheduled, or pid’s real-time priority is not changed, if the user is not a member of a
group having
PRIV_RTSCHED access and is not the user with appropriate privileges. When changing
the real-time priority of a currently executing process, the effective user ID of the calling process must be
the user with appropriate privileges, or the real or effective user ID must match the real or saved user ID
of the process to be modified.
In presence of processor sets (See pset_create (2) for details), the application execution is restricted to pro-
cessors in the application’s processor set. 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 processor set to choose the next thread to run.
RETURN VALUE
rtsched returns exit status:
HP-UX 11i Version 2: September 2004 − 1 − Hewlett-Packard Company Section 1−−815