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HP-UX 11i Version 3: February 2007

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pstat_getlocality(), pstat_getproclocality() — returns system-wide or per-process information of a ccNUMA system


#include <sys/pstat.h>

int pstat_getlocality( struct pst_locality *buf, size_t elemsize, size_t elemcount, int index ); int pstat_getproclocality( struct pst_proc_locality *buf, size_t elemsize, size_t pid, int index );


pstat_getlocality() and pstat_getproclocality() are part of the general pstat(2) functionality provided to obtain information about various system contexts. These calls return information on different parts of a Cache Coherent Non-Uniform Memory Architecture (ccNUMA) system. pstat_getlocality() returns system-wide information, while pstat_getproclocality() returns per-process information. A locality is one "building block" of a ccNUMA system. If a machine has only one locality, it is considered to be an UMA (Uniform Memory Architecture) machine. UMA is also a synonym for Symmetric Multiprocessor (SMP).

These locality building blocks are nearly identical to the concept of the locality domain (or LDOM) as described in the mpctl(2) manual page. From that manual page:

  • A locality domain consists of a related collection of processors, memory, and peripheral resources that comprise a fundamental building block of the system. All processors and peripheral devices in a given locality domain have equal latency to the memory contained within that locality domain.

There is only one difference between a locality and an LDOM, and that is the concept of interleaved memory. Interleaved memory is a hardware-constructed region of physical memory that is created from the memory of several locality domains. This memory is striped together with a very fine granularity. As an example, consider a system with four locality domains 0, 1, 2, and 3. Let's say they all contribute the same amount of memory to the interleave. The interleaved memory may look like this (assuming a 64-byte striping):

Memory Address Comes From -------------- ---------- 0 - 63 (bytes) LDOM 0 64 - 127 LDOM 1 128 - 191 LDOM 2 192 - 255 LDOM 3 256 - 319 LDOM 0 etc, etc

Interleaved memory is a good place to put shared objects, the kernel, and objects that could be accessed from any part of the system. There will be at most one interleaved locality. Some systems may not have interleaved memory.

Given the four-LDOM example above, these pstat() calls would return five localities - one for each LDOM, and one for interleaved memory. The reason that mpctl(2) does not count interleaved memory as an LDOM is because mpctl(2) is used for scheduling purposes, and interleaved memory contains no processors.

Function Descriptions


Returns system-wide information specific to each locality.

There is one instance of this context for each locality on the system. For each locality requested, data, up to a maximum of elemsize bytes, are returned in the struct pst_locality pointed to by buf. The elemcount parameter specifies the number of struct pst_locality that are available at buf to be filled in. The index parameter specifies the starting index within the context of localities.

The types and field members of the struct pst_locality are as follows:

pst_locality_flags_t psl_flags

Contains information about the given locality. See the description of pst_locality_flags_t below for details.

int64_t psl_ldom_id

This is the LDOM id used by mpctl(2) to identify this locality. For the interleaved locality, this field will be -1.

int64_t psl_physical_id

A hardware-based number that ties the locality to some recognizable physically indexable entity. An example of this is a cell id number.

uint64_t psl_total_pages

The total number of physical pages in this locality.

uint64_t psl_free_pages

The number of free physical pages in this locality at this moment.

uint64_t psl_cpus

The number of enabled cpus in this locality. This is irrespective of any processor sets that may be in effect for those cpus.

psl_flags is a bitfield described by the enumerated type pst_locality_flags_t . This field describes some of the properties of the locality. Valid values for pst_locality_flags_t are the following:


This locality is the interleaved locality.


This locality is not an interleaved locality. It will map to exactly one locality domain returned by the mpctl(2) system call. PSL_LOCAL and PSL_INTERLEAVED are mutually exclusive.


This locality does not contribute any physical memory to the interleave. PSL_FLOATING can only be set if PSL_LOCAL is also set.

On an UMA system, there will be one locality and PSL_LOCAL will be set in psl_flags.


Returns information specific to a particular process' locality behavior.

There is one instance of this context for each locality for each process on the system. For each instance requested, data, up to a maximum of elemsize bytes, are returned in the struct pst_proc_locality pointed to by buf. At most one instance (locality) is returned for each call to pstat_getproclocality(). The pid parameter specifies the process id of the process for which locality information is to be returned. A pid of zero indicates that locality information for the currently executing process should be returned. The index parameter specifies the starting index within the context of localities.

The types and field members of the struct pst_proc_locality are as follows:

int64_t ppl_ldom_id

This is the LDOM id used by mpctl(2) to identify this locality. For the interleaved locality, this field will be -1.

uint64_t ppl_rss_total

The total number of resident pages for this process in this locality.

uint64_t ppl_rss_shared

The number of shared resident pages for this process in this locality.

uint64_t ppl_rss_private

The number of private resident pages for this process in this locality.

uint64_t ppl_rss_weighted

The number of resident pages for this process in this locality, weighted by the number of processes sharing each page. Private pages count as one page, and shared pages count as the page divided by the number of processes sharing that page.


These functions only return the wide (64 bit) versions of their associated structures. In order for narrow (32 bit) applications to use these interfaces, the flag -D_PSTAT64 must be used at compile time. These interfaces are available for narrow applications written in standard C and extended ANSI, and for all wide applications.


pstat_getlocality() and pstat_getproclocality() return the following values:


Successful completion. n is the number of instances returned in buf .


Failure. errno is set to indicate the error.


Upon failure, errno is set to one of the following values.


buf points to an invalid address.


elemsize is less than or equal to zero, or elemsize is larger than the size of the associated data structure.


index is negative.


for pstat_getproclocality(), the requested pid could not be found.


/* * This program returns system-wide and per-process memory * locality information. To compile the 32-bit version, * use -D_PSTAT64. The 64-bit version does not need any * special compiler flags. */ #include <unistd.h> #include <stdio.h> #include <sys/param.h> #include <sys/pstat.h> #include <sys/errno.h> #define BURST ((size_t)3) #define STRSZ 80 unsigned long pgsize; void pid_locinfo ( pid_t pid ); void sys_locinfo ( void ); void pages_to_str ( uint64_t pages, char *str ); void usage ( int argc, char **argv ) { fprintf ( stderr, "Usage: %s [-p pid]\n", argv[0] ); fprintf ( stderr, "This program prints out per locality " ); fprintf ( stderr, "memory usage.\nIf 'pid' is supplied, " ); fprintf ( stderr, "information on that process is\n" ); fprintf ( stderr, "returned in addition to system-wide " ); fprintf ( stderr, "information.\n\n" ); exit(1); } /* * Verify arguments, call sys_locinfo(), and call pid_locinfo() * if desired. */ int main ( int argc, char **argv ) { pid_t pid = (pid_t) 0; if ( (argc == 2) || (argc > 3) || ((argc == 3) && (strncmp(argv[1], "-p", 2))) ) { usage(argc, argv); } if ( argc == 3 ) { pid = atoi(argv[2]); if (pid < 0) { /* note that pid 0 is "this process" */ usage(argc, argv); } } /* Get the size of a page for later calculations */ pgsize = sysconf ( _SC_PAGE_SIZE ); sys_locinfo(); if ( argc == 3 ) { pid_locinfo ( pid ); } return 0; } /* * Display the system-wide memory usage per locality. */ void sys_locinfo ( void ) { int i; /* index within pstl[] */ int count; /* the actual number of pstl structures */ int idx = 0; /* index within the context of localities */ struct pst_locality pstl[BURST]; char total_str[STRSZ], free_str[STRSZ], used_str[STRSZ]; uint64_t total=0, free=0; printf ( " --- System wide locality info: --- \n" ); printf ( "%6s%6s%7s%6s%10s%10s%10s\n", "index", "ldom", "physid", "type", "total", "free", "used" ); /* Get a maximum of BURST pst_locality structures */ count = pstat_getlocality ( pstl, sizeof(struct pst_locality), BURST, idx ); while ( count > 0 ) { for ( i=0 ; i<count ; i++ ) { /* Keep running totals for later */ total += pstl[i].psl_total_pages; free += pstl[i].psl_free_pages; /* Convert integers into strings */ pages_to_str ( pstl[i].psl_total_pages, total_str ); pages_to_str ( pstl[i].psl_free_pages, free_str ); pages_to_str ( (pstl[i].psl_total_pages - pstl[i].psl_free_pages), used_str ); printf ( "%6d%6lld%7lld%6s%10s%10s%10s\n", (idx+i), pstl[i].psl_ldom_id, pstl[i].psl_physical_id, ((pstl[i].psl_flags & PSL_INTERLEAVED) ? "ILV":"CLM"), total_str, free_str, used_str ); } idx += count; /* * Get (at most) the next BURST pst_locality * structures, starting at idx */ count = pstat_getlocality ( pstl, sizeof(struct pst_locality), BURST, idx ); } if ( count < 0 ) { perror ( "pstat_getlocality" ); exit(1); } if ( idx == 1 ) { /* Don't print totals if there's one locality */ printf ( "\n" ); return; } /* Convert integer totals into strings */ pages_to_str ( total, total_str ); pages_to_str ( free, free_str ); pages_to_str ( total-free, used_str ); /* Print totals */ printf ( "%6s%6s%7s%6s%10s%10s%10s\n", "", "", "", "", "-----", "-----", "-----" ); printf ( "%6s%6s%7s%6s%10s%10s%10s\n\n", "", "", "", "", total_str, free_str, used_str ); } /* * Given a pid, display its per-locality physical memory usage. */ void pid_locinfo ( pid_t pid ) { int count, i=0; struct pst_proc_locality ppl; char total_str[STRSZ], shared_str[STRSZ]; char private_str[STRSZ], weighted_str[STRSZ]; uint64_t total=0, shared=0, private=0, weighted=0; /* * With this interface, information on only one locality * can be returned at a time. This will get the first: */ count = pstat_getproclocality ( &ppl, sizeof(struct pst_proc_locality), pid, i ); printf ( " --- Per-process locality info for pid %d: ---\n", pid ); printf ( "%6s%10s%10s%10s%10s\n", "idx", "total", "shared", "private", "weighted" ); while ( count == 1 ) { total += ppl.ppl_rss_total; shared += ppl.ppl_rss_shared; private += ppl.ppl_rss_private; weighted += ppl.ppl_rss_weighted; pages_to_str ( ppl.ppl_rss_total, total_str ); pages_to_str ( ppl.ppl_rss_shared, shared_str ); pages_to_str ( ppl.ppl_rss_private, private_str ); pages_to_str ( ppl.ppl_rss_weighted, weighted_str ); printf ( "%6d%10s%10s%10s%10s\n", i, total_str, shared_str, private_str, weighted_str ); i++; count = pstat_getproclocality ( &ppl, sizeof(struct pst_proc_locality), pid, i ); } if ( count < 0 ) { if ( errno == ESRCH ) { fprintf ( stderr, "Process %d not found\n", pid ); exit(1); } perror ( "pstat_getproclocality" ); exit(1); } if ( i == 1 ) { /* Don't print totals if there's one locality */ printf ( "\n" ); return; } pages_to_str ( total, total_str ); pages_to_str ( shared, shared_str ); pages_to_str ( private, private_str ); pages_to_str ( weighted, weighted_str ); printf ( "%6s%10s%10s%10s%10s\n", "", "-----", "-----", "-----", "-----" ); printf ( "%6s%10s%10s%10s%10s\n\n", "", total_str, shared_str, private_str, weighted_str ); } /* * Given a quantity of memory in pages, fill str with a * human-readable string representing that amount. */ void pages_to_str ( uint64_t pages, char *str ) { uint64_t kpg = pages*(pgsize/1024L); uint64_t mpg = kpg/1024L; uint64_t gpg = mpg/1024L; if ( gpg > 10 ) { sprintf ( str, "%lluG", gpg ); } else if ( mpg > 10 ) { sprintf ( str, "%lluM", mpg ); } else if ( kpg > 1 ) { sprintf ( str, "%lluK", kpg ); } else { sprintf ( str, "%llu", pages ); } }


The pstat routines were developed by Hewlett-Packard Company.


pstat(2), mpctl(2).

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