HP-UX Processor Sets

HP-UX Processor Sets 14
PSET_ATTR_EMPTY
Indicates the behavior when a request to bind a process or a thread to an empty
processor set is made. An empty processor set has no processors assigned to it.
Currently, only the following value is supported:
PSET_ATTRVAL_FAIL Reject the request. This is the default value for this
attribute.
PSET_ATTR_LASTSPU
Indicates the behavior when a request to remove the last processor from a processor
set is made. A processor may be removed from a processor set to be reassigned to
another processor set, or to be disabled from processing any workload in the system.
The following values are supported:
PSET_ATTRVAL_FAIL Fail the request if there are active threads and
processes assigned to the processor set.
PSET_ATTRVAL_DFLTPSET Remove the processor from the processor set,
and migrate all threads and processes to the
Default Pset. This is the default value for this
attribute.
The Default Pset
HP-UX systems start with one user-visible processor set when booted: the Default Pset.
During system initialization, all enabled processors in the system are assigned to the Default
Pset, which is assigned the unique psetid of PS_DEFAULT. The Default Pset has special
significance in the HP-UX Processor Sets model. Its key features are as follows:
ÿ The Default Pset can never be destroyed.
ÿ Processor 0 is always assigned to the Default Pset, and cannot be reassigned to any
other user-created processor set.
ÿ The superuser is the Default Pset owner and can never be changed.
ÿ The superuser or a PRIV_PSET privileged user may reassign any processor (except
Processor 0) out of the Default Pset to other user-created processor sets .
ÿ The Default Pset is always accessible to all applications and users in the system. Its
access permissions cannot be changed to restrict access to any users.
ÿ The Default Pset acts as the final home for the deserted. When a processor set is
destroyed, all applications and processors in that processor set are reassigned to the