rtsched(1)                                                       rtsched(1)




 NAME    [Toc]    [Back]
      rtsched - execute process with real-time priority

 SYNOPSIS    [Toc]    [Back]
      rtsched -s scheduler -p priority command [arguments]

      rtsched [ -s scheduler ] -p priority -P pid

 DESCRIPTION    [Toc]    [Back]
      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    [Toc]    [Back]
      -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 corresponding
                     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



 Hewlett-Packard Company            - 1 -   HP-UX 11i Version 2: August 2003






 rtsched(1)                                                       rtsched(1)




                     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 realtime
 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 realtime
 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 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    [Toc]    [Back]
      rtsched returns exit status:

           0       if command is successfully scheduled or if pid's realtime
 priority is successfully changed;

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

           2       if command (pid) lacks real-time capability, or the
                   invoker's effective user ID is not a user who has
                   appropriate privileges, 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

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

 EXAMPLES    [Toc]    [Back]
      Execute file a.out with SCHED_FIFO at a priority of 10:

           rtsched -s SCHED_FIFO -p 10 a.out

      Execute file a.out with SCHED_RTPRIO at a priority of 127 (this is
      synonymous to rtprio 127 a.out):





 Hewlett-Packard Company            - 2 -   HP-UX 11i Version 2: August 2003






 rtsched(1)                                                       rtsched(1)




           rtsched -s SCHED_RTPRIO -p 127 a.out

      Execute file a.out with the SCHED_HPUX scheduler:

           rtsched -s SCHED_HPUX a.out

      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:

           rtsched -s SCHED_RR2 -p 20 -P 24217

      Now change its priority to 10 using the same scheduler:

           rtsched -p 10 -P 24217

 WARNINGS    [Toc]    [Back]
      Priority values used by rtsched may differ from those used by other
      commands.  For example, ps(1) displays the internal representation of
      priority values.

 AUTHOR    [Toc]    [Back]
      rtsched was developed by HP.

 SEE ALSO    [Toc]    [Back]
      rtprio(1), setprivgrp(1M), getprivgrp(2), pset_create(2), rtprio(2),
      rtsched(2).


 Hewlett-Packard Company            - 3 -   HP-UX 11i Version 2: August 2003