pstat_getlocality(2)pstat_getlocality(2)NAMEpstat_getlocality(), pstat_getproclocality() - returns system-wide or
per-process information of a ccNUMA system
SYNOPSISDESCRIPTION
and are part of the general functionality provided to obtain informa‐
tion about various system contexts.
These calls return information on different parts of a Cache Coherent
Non-Uniform Memory Architecture (ccNUMA) system. returns system-wide
information, while returns per-process information. A locality is one
"building block" of a ccNUMA system. If a machine has only one local‐
ity, 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 proces‐
sors, memory, and peripheral resources that comprise a fundamen‐
tal 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 hard‐
ware-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 calls would return five local‐
ities - 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 con‐
tains 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 pointed to by buf. The
elemcount parameter specifies the number of 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 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 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 prop‐
erties 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. and are mutually
exclusive.
This locality does not contribute any physical memory to the
interleave. can only be set if is also
set.
On an UMA system, there will be one locality and will be set in
psl_flags.
Returns information specific to a particular process' locality behav‐
ior.
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 pointed
to by buf. At most one instance (locality) is returned for
each call to 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 cur‐
rently executing process should be returned. The index parame‐
ter specifies the starting index within the context of locali‐
ties.
The types and field members of the 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 pro‐
cesses sharing that page.
Notes
These functions only return the wide (64 bit) versions of their associ‐
ated structures. In order for narrow (32 bit) applications to use
these interfaces, the flag must be used at compile time. These inter‐
faces are available for narrow applications written in standard C and
extended ANSI, and for all wide applications.
RETURN VALUE
and return the following values:
Successful completion.
n is the number of instances returned in buf .
Failure.
is set to indicate the error.
ERRORS
Upon failure, is set to one of the following values.
[EFAULT] buf points to an invalid address.
[EINVAL] elemsize is less than or equal to zero, or elem‐
size is larger than the size of the associated
data structure.
[EINVAL] index is negative.
[ESRCH] for pstat_getproclocality(), the requested pid
could not be found.
EXAMPLES
/*
* 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 );
}
}
AUTHOR
The routines were developed by Hewlett-Packard Company.
SEE ALSOpstat(2), mpctl(2).
pstat_getlocality(2)
