HP-UX Reference (11i v2 03/08) - 2 System Calls (vol 5)

p
pset_assign(2) pset_assign(2)
NAME
pset_assign - change processor set assignment
SYNOPSIS
#include <sys/pset.h>
int pset_assign(
psetid_t pset,
spu_t spu,
psetid_t *opset);
DESCRIPTION
The pset_assign()
function assigns the processor spu to the processor set pset , removing the proces-
sor 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 NULL, it contains the processor set ID of the previously assigned processor set
upon successful operation.
A superuser, a PRIV_PSET privilege user, or a user with WRITE permissions on the processor sets may
change the processor set assignment for a processor using
pset_assign() function. A user other than
superuser or without PRIV_PSET privileges 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 superuser or a PRIV_PSET privilege user 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
PS_DEFAULT or PS_NONE, the processor spu is assigned to the system default processor set.
If pset is
PS_QUERY, the processor’s assignment is not changed, but the current processor set ID of pro-
cessor spu is returned in opset. No superuser access or WRITE permission is needed for PS_QUERY
operation.
If there are threads or processes with binding to the processor spu (in its old processor set), the binding of
affected threads and processes is changed to another processor in that processor set. If spu is the last pro-
cessor 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
pset_assign()
is dependent on
the value of the
PSET_ATTR_LASTSPU
attribute. The following attribute values are defined for this
attribute:
PSET_ATTRVAL_DFLTPSET
Assign the processor to the specified processor set, and migrate all threads and processes to the
system default processor set,
PS_DEFAULT. 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.
PSET_ATTRVAL_FAIL
Make the request fail if there are active threads and processes assigned to the processor set.
EXAMPLE
Reassign spu from its current processor set to new_pset , and retrieve the current processor set in
old_pset .
#include <sys/pset.h>
spu_t spu;
psetid_t new_pset, old_pset;
int ret;
/*
* Initialize spu and new_pset first.
* spu identifies the processor to be reassigned, whereas
* new_pset identifies the target processor set.
*/
if ((ret = pset_assign(new_pset, spu, &old_pset)) < 0) {
HP-UX 11i Version 2: August 2003 − 1 − Hewlett-Packard Company Section 2−−221