pset_ctl(2)

NAME

pset_ctl — processor set control

SYNOPSIS

#include <sys/pset.h> 

int pset_ctl(
pset_request_t request,
psetid_t       pset,
id_t           id
);

DESCRIPTION

The pset_ctl() function provides a means to query the system processor set configuration and assignment information. The request argument specifies what information is needed for the pset processor set. The following request values are supported:

PSET_GETCURRENTPSET

Return the ID of the processor set binding for the calling thread. The pset and id arguments are ignored.

PSET_GETFIRSTLDOM

Return the ID of the first locality domain contributing to the processor set pset. The id argument is ignored.

PSET_GETFIRSTPSET

Return the ID of the first processor set in the system. The pset and id arguments are ignored.

PSET_GETFIRSTSPU

Return the ID of the first processor in the processor set pset. It will return -1 if the processor set is empty. Any processors in the processor set that is in transition are ignored. The id argument is ignored.

PSET_GETNEXTLDOM

Return the ID of the next locality domain after the locality domain specified in id that contributes to the processor set pset.

Typically, PSET_GETFIRSTLDOM is called to determine the first locality domain in a processor set. PSET_GETNEXTLDOM is then called in a loop (until the call returns -1) to determine the IDs of the remaining locality domain in the processor set.

PSET_GETNEXTPSET

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

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

PSET_GETNEXTSPU

Return the ID of next processor in the processor set pset after the processor specified in id.

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

PSET_GETNUMLDOMS

Return the number of locality domains that have at least one processor assigned to the processor set pset. The id argument is ignored.

PSET_GETNUMPSETS

Return the current number of processor sets in the system. It will always be greater than or equal to one. The pset and id arguments are ignored.

PSET_GETNUMSPUS

Return the number of processors assigned to the processor set pset. Any processors in the processor set that is in transition are not included. The id argument is ignored.

PSET_LDOMSPUS

Return number of processors contributed by the locality domain specified by id to the processor set pset.

PSET_SPUTOPSET

Return the ID of the processor set assigned for the processor specified in id. If the processor is not enabled or is in transition from one processor set to another, -1 is returned with an error. The pset argument is ignored.

Logical Processor and Processor Core Information

On systems with the Hyper-Threading (HT) feature enabled, each processor core may have more than one hyper-thread per physical processor core. When hyper-threading is enabled at the firmware level, each hyper-thread is represented to the operating system and applications as a logical processor (LCPU). Hence the basic unit of any topology information is a logical processor. However, some applications may want to get the system topology information at the physical processor core level.

PSET_GETNUMCORES: Returns the number of processor cores assigned to the processor set pset. Any processor cores in the processor set that are in transition are not included. The id argument is ignored.
PSET_GETFIRSTCORE: Returns the ID of the first processor core in the processor set pset. It will return -1 if the processor set is empty. Any processor cores in the processor set that is in transition are ignored. The id argument is ignored.
PSET_GETNEXTCORE: Returns the ID of the next processor core in the processor set pset after the processor specified in id. Typically, PSET_GETFIRSTCORE is called to determine the first processor core in a processor set. PSET_GETNEXTCORE is then called in a loop (until the call returns -1) to determine the IDs of remaining processor cores in the processor set.
PSET_LDOMCORES: Returns the number of enabled processor cores assigned to the processor set pset.

Any user may query the system processor set topology using the pset_ctl() function.

Use sysconf() with _SC_PSET_SUPPORT name to see if the processor set functionality is supported by the underlying HP-UX operating system version.

RETURN VALUE

pset_ctl() returns a value based on on successful completion.

>=0: Success. The value is based on the request.
-1: Failure. errno is set to indicate the error.

ERRORS

pset_ctl() sets errno to one of the following values if the corresponding condition is detected.

EINVAL: The request is invalid.
EINVAL: The specified processor set pset, or the processor or the locality domain specified by id is invalid.
EINVAL: The request is PSET_GETNEXTPSET and there is no other processor set after pset, or the request is PSET_GETNEXTSPU and there is no other processor after id in pset, or the request is PSET_GETNEXTLDOM and there is no other locality domain after id in pset.
ENOSYS: The processor set functionality is not supported by the underlying HP-UX version.

EXAMPLES

Get total count and IDs of all processor sets in the system.

#include <sys/pset.h> 

/* 
 * Get list of all processor sets in the system. 
 */ 
psetid_t    *all_psets; 
int         pset_count, idx; 
psetid_t    pset; 

/* Get total count of processor sets in the system */ 
pset_count = pset_ctl(PSET_GETNUMPSETS, 0, 0); 
if (pset_count < 1) { 
    perror("pset_ctl(PSET_GETNUMPSETS)"); 
    exit(1); 
} 

all_psets = (psetid_t *) malloc(sizeof(psetid_t)*pset_count); 
memset(all_psets, 0, sizeof(psetid_t)*pset_count); 
idx = 0; 

/* Get first processor set */ 
pset = pset_ctl(PSET_GETFIRSTPSET, 0, 0); 
if (pset < 0) { 
    perror("pset_ctl(PSET_GETFIRSTPSET)"); 
    exit(2); 
} 
all_psets[idx++] = pset; 

/* Get remaining processor sets */ 
while (idx < pset_count) { 
    pset = pset_ctl(PSET_GETNEXTPSET, pset, 0); 
    if (pset < 0) { 
        perror("pset_ctl(PSET_GETNEXTPSET)"); 
        exit(3); 
    } else { 
        all_psets[idx++] = pset; 
    } 
} 

AUTHOR

pset_ctl() was developed by HP.

pset_ctl(2)

Technical documentation

» Table of Contents

» Index