rtsched(1)						      General Commands Manual							rtsched(1)

NAME

       rtsched - execute process/lightweight process (LWP) with real-time priority

SYNOPSIS

       scheduler priority command [arguments]

       scheduler] priority

       scheduler] priority

       scheduler] priority

DESCRIPTION

       executes  command  with POSIX or HP-UX real-time priority, or changes the real-time priority of currently executing process (pid) or light-
       weight process (lwpid).

       All POSIX real-time priority processes or LWPs are of greater scheduling importance than processes/LWPs with HP-UX real-time or HP-UX time-
       share  priority.   All  HP-UX  real-time  priority  processes/LWPs  are of greater scheduling importance than HP-UX timeshare priority pro-
       cesses/LWPs, but are of lesser importance than POSIX real-time processes/LWPs.

       Neither POSIX nor HP-UX real-time processes/LWPs are subject to degradation.

       POSIX real-time processes/LWPs may be scheduled with one of three different POSIX real-time schedulers: SCHED_FIFO, SCHED_RR, or SCHED_RR2.
       See rtsched(2) for details.

       is a superset of See rtprio(1).

   Options
       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

       Specify priority range;
		      any  integer  within  the  inclusive  priority  range of the corresponding scheduler.  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

		      Higher numerical values for the priority represent higher priorities under POSIX real-time schedulers, whereas lower numeri-
		      cal values for the priority represent higher priorities under HP-UX real-time and timeshare schedulers.

       Specify an already executing
		      process ID (pid).

       Specify an already executing
		      lightweight process ID (lwpid).  The target LWP (lwpid) can be in any process.

       Select all the LWPs in an already executing
		      process (specified with When scheduling policy is not specified explicitly using the option, the process's current  schedul-
		      ing  policy will be used.  If the requested priority value is in the range for this scheduling policy, the scheduling policy
		      and priority of the process and all its LWPs will be changed to these values.  Please note that it may cause the	scheduling
		      policy to be changed for some LWPs.

       If  the	user is not a member of a group having access and is not the user with appropriate privileges, command is not scheduled, or pid's/
       lwpid's real-time priority is not changed.  When changing the real-time priority of a currently executing process/LWP, 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 processors 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

       returns exit status:

	      if   command is successfully scheduled or if pid's or lwpid's real-time priority is successfully changed;

	      if   command is not executable, pid or lwpid does not exist, or priority is not within the  priority  range  for	the  corresponding
		   scheduler;

	      if   command  (pid/lwpid)  lacks	real-time  capability, or the invoker's effective user ID is not a user who has appropriate privi-
		   leges, or the real or effective user or the real or effective user ID does not match the real or saved user ID of  the  process
		   being changed; or

	      if rtsched encountered an internal
		   error or if rtsched is not supported by this release.

EXAMPLES

       Execute file with SCHED_FIFO at a priority of 10:

       Execute file with SCHED_RTPRIO at a priority of 127 (this is synonymous to

       Execute file with the SCHED_HPUX scheduler:

       This is useful to spawn a timeshare priority command from a real-time priority shell.

       Set the currently running process, pid 24217, to execute with SCHED_RR2 at a priority of 20:

       Now change its priority to 10 using the same scheduler:

       Set the currently running LWP, lwpid 987312, to execute with SCHED_RR at a priority of 10:

       Set all currently executing LWPs in a process pid 21342 to execute with SCHED_FIFO at a priority of 25:

WARNINGS

       The  priority values used by may differ from those used by other commands.  For example, ps(1) displays the internal representation of pri-
       ority values.

AUTHOR

       was developed by HP.

SEE ALSO

       rtprio(1),   setprivgrp(1M),   getprivgrp(2),   pset_create(2),	 rtprio(2),   rtsched(2),   _lwp_getscheduler(2),    _lwp_setscheduler(2),
       pstat_getlwp(2).

																	rtsched(1)