__pset_rtctl(2) 						System Calls Manual						   __pset_rtctl(2)

NAME

       __pset_rtctl() - real-time processor set control

SYNOPSIS


DESCRIPTION

       HP-UX  Processor Sets allow a subset of processors in the system to be isolated for exclusive use by specified threads and processes.  Only
       the threads bound to a processor set can execute on processors in that processor set (see pset_create(2)).

       The function extends processor set functionality for real-time applications to minimize operating system activities in a processor set.	 A
       processor  set  can  be configured as a real-time processor set (referred to as RTE processor set).  An RTE processor set has the following
       special features that are not available in standard processor sets:

       The scheduler does not schedule kernel daemons on processors in the
	    RTE processor set.	Kernel daemons are restricted to processors in non-RTE processor sets.

       External I/O interrupts on processors in the RTE processor set are disabled.
	    The system is reconfigured to not deliver any external I/O interrupts to processors in the RTE processor set.   (The  clock  interrupt
	    still continues to come on each processor though).	This feature may not be supported on all platforms (see intctl(1M) for details).

       All pending callouts on processors in the RTE processor set are reassigned to
	    processors	in  non-RTE processor sets.  However, if a real-time application in an RTE processor set requests a service which requires
	    callout support in the kernel, such callouts may execute on RTE processors.

       The system always has at least one non-RTE processor set.  The system default processor set (see pset_create(2)) cannot be configured as an
       RTE  processor  set.   Since the system default processor set is never empty, there is always at least one processor in a non-RTE processor
       set to execute the kernel daemons, I/O interrupts and callouts for the system.

       The request argument specifies the operation to perform on the processor set pset for real time extension.  The following values  are  sup-
       ported:
       Configure  the  specified  processor set, pset, as an RTE processor set.  The processor set may or may not have processors assigned at this
       point.  If pset has processors assigned to it at the time of this request, these processors are made unavailable  to  the  kernel  daemons.
       External  I/O  interrupts  and pending callouts on processors in pset are reassigned to processors in non-RTE processor sets in the system.
       The processor set attribute values are changed to default values for an RTE processor set.  If pset has any assigned workload, it continues
       to execute in that processor set.  The arg argument is ignored.

       Unconfigure the specified processor set
	      pset  as	an RTE processor set.  The processors, if any, in this processor set are made available to the kernel daemons.	The system
	      may redistribute the external I/O interrupts with availability of these processors.  Pending callouts in the system are  not  redis-
	      tributed	to  these  processors.	 The  processor set attribute values are restored to default values for a non-RTE processor set as
	      applicable.  If pset has any assigned workload, it continues to execute in that processor set.  The arg argument is ignored.  Return
	      the ID of the first RTE processor set in the system.  The pset and arg arguments are ignored.

       Return the ID of the next RTE processor set in the system after
	      pset.  The arg argument is ignored.

	      Typically,  is  called  to determine the first RTE processor set.  is then called in a loop (until the call returns -1) to determine
	      the IDs of the remaining RTE processor sets in the system.

       See pset_ctl(2) for additional processor set query operations.  The function allows users to query all processor sets in the  system,  pro-
       cessors in a specific processor set, processor set given a processor, etc.

       A  processor  may  be added to an RTE processor set using the function.	In this case, the processor is made unavailable to the kernel dae-
       mons; external I/O interrupts and pending callouts on this processor are reassigned to processors in non-RTE processor sets in the  system.
       Conversely,  if	a  processor is removed from an RTE processor set and added to a non-RTE processor set, it is made available to the kernel
       daemons and for external I/O interrupts.  Similarly, if a non-empty RTE processor set is destroyed, its processors are  made  available	to
       the kernel daemons and for external I/O interrupts.

       Only  a	user with appropriate privileges may configure and unconfigure an RTE processor set.  However, any user may query the IDs and con-
       figuration of RTE processor sets.  Only a user with appropriate privileges may reassign processors into or out of  an  RTE  processor  set,
       change  attribute  values, or destroy an RTE processor set.  Any user with EXEC permissions in an RTE processor set may run applications in
       that RTE processor set.

       HP-UX processor sets define processor set attributes to provide users explicit control in managing their processor  set	configuration  and
       work  load  assignment among many users and applications (see pset_getattr(2) for details).  A processor set is assigned default values for
       these attributes at creation time.  The RTE processor sets attributes are assigned different default values at time of configuration.   The
       supported attributes and their default values are:

       UID of the processor set owner.	When a processor set is converted into an RTE pset, the owner of the pset changes to that of the effective
       uid of the calling process.  The owner  of  the	pset  or  a  user  with  appropriate  privilege  can  change  this  attribute  using  (See
       pset_setattr(2).)

       GID of processor set's owner group.
	      When  a  processor  set  is  converted  into  an RTE pset, the group of the pset changes to that of the effective gid of the calling
	      process.	The owner of the pset or a user with appropriate privilege can change this attribute using (See pset_setattr(2).)

       Access permissions for the processor set.
	      When a processor set is converted to an RTE processor set, the permissions are reset such that the processor set owner has all  per-
	      missions,  group	has READ and EXEC permissions, and others have only READ permissions.  The owner of the pset or a user with appro-
	      priate privileges can change this attribute using (See pset_setattr(2).)

       Indicates the behavior on a request to bind a process
	      or a thread to a processor set that does not contain any processors.  For RTE processor sets, such a request is rejected by default.
	      However,	a user with appropriate privileges or a user with WRITE access to the pset can change the value of this attribute to allow
	      deletion of an empty RTE processor set.  See pset_getattr(2) for supported values.

       A flag to indicate if processors in the processor set are
	      configured to receive external I/O interrupts or not.  All processors in an RTE processor set are disabled  to  receive  interrupts.
	      This attribute cannot be enabled until the processor set is unconfigured as an RTE processor set.

       Indicates the behavior on a request to remove the last processor from a
	      processor  set  if  there  are  active  processes and threads bound to the processor set.  For RTE processor sets, such a request is
	      rejected by default.  However, a user with appropriate privileges or a user with WRITE access to the pset can change  the  value	of
	      this  attribute  to  allow  removal  of  the  last  processor  from  an  RTE  processor  set even if the processor set is busy.  See
	      pset_setattr(2) for supported values.

       Indicates the behavior on a request to destroy a non-empty processor set.
	      A non-empty processor set has at least one processor assigned to it.  For RTE processor sets, such a request  will  be  rejected	by
	      default.	However, a user with appropriate privileges or a user with WRITE access to the pset can change the value of this attribute
	      to allow deletion of an RTE processor set in use.  See pset_setattr(2) for supported values.

       Indicates whether the physical processor cores in the RTE pset is enabled
	      with logical processors (LCPUs).	See pset_setattr(2) for details and supported values.

   Processor Set Support
       Use with to see if the processor set functionality is supported by the underlying HP-UX operating system version.

       Use with to see if the RTE processor set functionality is supported by the underlying HP-UX operating system version.

   Security Restrictions
       Some or all of the actions associated with this system call require the privilege.  Processes owned by the superuser have  this	privilege.
       Processes  owned  by  other users may have this privilege, depending on system configuration.  See privileges(5) for more information about
       privileged access on systems that support fine-grained privileges.

RETURN VALUE

       returns zero on successful completion for and requests.

       For and requests, the ID of an RTE processor set is returned if one is found.

       Otherwise, is returned and is set to indicate the error.

ERRORS

       fails if one or more of the following is true:

       The specified processor set
		      pset is already configured as RTE processor set, and the request is issued.

       The	      request is invalid.

       The specified processor set
		      pset is invalid.

       The specified processor set
		      pset is not an RTE processor set, and request is issued.

       The request is and there is no other RTE processor set after pset.

       The RTE processor set functionality is not supported by the
		      underlying HP-UX version.

       The user does not have necessary permissions to perform the requested
		      operation.

       The specified processor set,
		      pset, is a special, reserved processor set, and cannot be configured as an RTE processor set.

EXAMPLES

       Create a new processor set, and configure it as an RTE processor set:

SEE ALSO

       psrset(1M), pset_assign(2), pset_bind(2), pset_ctl(2), pset_destroy(2), pset_getattr(2), pset_setattr(2), sysconf(2), privileges(5).

																   __pset_rtctl(2)