hpux man page for pset_assign

pset_assign(2)							System Calls Manual						    pset_assign(2)

NAME
       pset_assign() - change processor set assignment

SYNOPSIS

DESCRIPTION
       The  function  assigns the processor spu to the processor set pset, removing the processor spu from its current processor set.  A processor
       may not belong to more than one processor set at any given time.  If opset is not it contains  the  processor  set  ID  of  the	previously
       assigned processor set upon successful operation.

       A  user	with  the privilege or a user with WRITE permissions on the processor sets may change the processor set assignment for a processor
       using the function.  A user without the privilege must have WRITE permissions in both processor sets to make  the  processor  reassignment,
       unless  the  target processor set is the system default processor set.  That is, only a user with the privilege may move a processor out of
       the system default processor set.

       Currently, processor 0 cannot be reassigned to another processor set from the system default processor set.  The system	default  processor
       set is never empty.

       If pset is or the processor spu is assigned to the system default processor set.

       If  pset  is  the  processor's  assignment is not changed, but the current processor set ID of processor spu is returned in opset.  Neither
       WRITE permission nor the privilege is needed for operation.

       If there are threads or processes with binding to the processor spu (in its old processor set), the binding of affected	threads  and  pro-
       cesses  is changed to another processor in that processor set.  If spu is the last processor in the locality domain that contributes to its
       current processor set and there are threads or processes with binding to the locality domain, their binding is changed to another  locality
       domain in the processor set.  See mpctl(2) for binding to processors and locality domains.

       If  spu	is  the  last  processor  in its current processor set, the behavior of is dependent on the value of the attribute.  The following
       attribute values are defined for this attribute:

       Assign the processor to the specified processor
		 set, and migrate all threads and processes to the system default processor set, This is the default behavior.	If the threads and
		 processes  being  migrated to the system default processor set (pset) have binding to processor or locality domain, their binding
		 is reassigned to another processor or locality domain in the system default processor set.

       Make the request fail if there are active threads
		 and processes assigned to the processor set.

   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.

   Note on Logical Processor and Hyper-Threading Feature
       On systems with the Hyper-Threading (HT) feature enabled at the firmware, each hyper-thread is represented as a logical processor (LCPU).

       For migration of a logical processor in a processor core may also migrate that logical processor's sibling logical processor, which belongs
       to  the same physical processor core.  Otherwise the resulting configuration would violate the processor set contract, which specifies that
       applications bound to a processor set have complete and exclusive control of all processor cores within that processor set.

       When a processor core is assigned to another pset, depending on the source and target processor sets' (see pset_setattr(2)) value, the num-
       ber of logical processors from that processor core may change.

EXAMPLES
       Reassign spu from its current processor set to new_pset, and retrieve the current processor set in old_pset.

RETURN VALUE
       returns zero on successful completion.  Otherwise, -1 is returned and is set to indicate the error.

ERRORS
       fails if one or more of the following is true:

       The processor set currently assigned to the processor
		    spu has active threads and processes, and the processor set attributes do not allow this operation.

       The memory location pointed to by
		    opset is not writable by the user.

       The operation was interrupted.

       The processor
		    spu or processor set pset is not valid.

       The	    spu is not enabled.

       The memory location pointed to by
		    opset is and the operation is requested.

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

       The user does not have necessary permissions to assign
		    spu to pset.

SEE ALSO
       mpctl(2), pset_bind(2), pset_create(2), pset_ctl(2), pset_destroy(2), pset_getattr(2), pset_setattr(2), privgrp(4), privileges(5).

																    pset_assign(2)