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rad_get_num(3)
NAME
rad_get_num, rad_get_cpus, rad_get_freemem, rad_get_info, rad_get_max,
rad_get_physmem, rad_get_state - Query resource complements of a Resource
Affinity Domain (libnuma)
SYNOPSIS
#include <numa.h>
int rad_get_cpus(
radid_t rad,
cpuset_t cpuset );
ssize_t rad_get_freemem(
radid_t rad );
int rad_get_info(
radid_t rad,
rad_info_t *info );
int rad_get_max(
void );
int rad_get_num(
void );
ssize_t rad_get_physmem(
radid_t rad );
ssize_t rad_get_state(
radid_t rad );
PARAMETERS
cpuset Specifies a buffer to receive the CPU set assigned to the specified
Resource Affinity Domain (RAD) in the caller's partition
info Points to a buffer to receive information about the specified RAD.
rad Identifies the RAD for which the resource complement is being
requested.
DESCRIPTION
A Resource Affinity Domain (RAD) is a collection of resources that are
related by the platform hardware topology. The collection of processors and
I/O buses connected to a local memory of a NUMA platform, plus the local
memory itself, comprise a RAD. More generally, a RAD may be characterized
as a set of resources that are within some "distance" of each other.
The rad_get_info() function stores in the buffer pointed to by info, a
rad_info_t structure containing information about the RAD specified by the
radid argument. This information includes the state of the RAD, the amount
of memory in the RAD, and the CPUs it contains. The remaining functions on
this reference page return individual members of the rad_info_t structure.
The rad_get_cpus() function stores in the buffer specified by cpuset the
set of CPUs in the specified RAD that are assigned to the caller's
partition.
The rad_get_freemem() function returns a snapshot of the amount of free
memory (pages) in the specified RAD in the caller's partition.
The rad_get_max() function returns the maximum number of RADs on the
system.
The rad_get_num() function returns the number of RADs in the caller's
partition.
The rad_get_physmem() function returns the amount of physical memory
(pages) assigned to the specified RAD in the caller's partition.
The rad_get_state() function returns the current state of the RAD specified
by the radid argument. The possible RAD state values are:
RAD_ONLINE
The specified RAD exists and is on line. Processes and threads may
be assigned to the RAD and memory may be allocated there.
RAD_OFFLINE
The specified RAD exists but is not currently on line. Neither
processes nor threads may be assigned to this RAD, and no memory
may be allocated there. However, the RAD's resource complement may
be queried.
Note
Currently, RAD state is always set to RAD_ONLINE; therefore,
consider this function as being reserved for future use.
Note that prior to calling any of the rad_get_*() functions, the
application must set the rinfo_version field in the rad_info_t structure to
RAD_INFO_VERSION. The CPU set (cpuset) stored in this structure must have
been created by the application prior to the call. If zero is specified for
cpuset, the function does not fill in data for the CPU set.
RESTRICTIONS
As with many queries of system information, the data returned by these
functions may be stale by the time it is returned to or used by the calling
application.
RETURN VALUES
The rad_get_info() and rad_get_cpus() functions return the following
values:
0 or positive integer
Success. In this case, the integer value is the number of CPUs
in the specified RAD.
-1 Failure. In this case, errno is set to indicate the error.
The rad_get_freemem() and rad_get_physmem() functions return the following:
Number of pages of memory
Success. Depending on the function, this value is the amount of
free memory for the specified RAD or the amount of physical
memory assigned to the RAD.
(ssize_t)-1 Failure. In this case, errno is set to indicate the error.
The rad_get_num() and rad_get_max() functions return the number of RADs in
the caller's partition or on the system, respectively. There is no value
defined to indicate failure for these functions.
The rad_get_state() function always returns a state value. There is no
value defined to indicate failure for this function.
ERRORS
The rad_get_cpus(), rad_get_info(), rad_get_freemem(), and
rad_get_physmem() functions set errno to one of the following values for
the specified condition:
[EFAULT] The cpuset argument indirectly points to an invalid address, or
the specified CPU set does not exist, possibly because it was
not created by a call to cpusetcreate().
[EINVAL] The rad argument specifies a RAD that does not exist.
[EPERM] The version number specified for the rinfo_version field in the
info argument is not recognized by the system.
EXAMPLES
The following example prints data returned by a call to rad_get_info():
#include <sys/errno.h>
#include <numa.h>
int
print_rad_info(radid_t rad)
{
rad_info_t radinfo;
/* Create a cpuset for the radinfo struct. */
cpusetcreate(&radinfo.rinfo_cpuset);
radinfo.rinfo_version = RAD_INFO_VERSION;
/* Fetch the data */
if (rad_get_info(rad, &radinfo) == -1) {
perror("rad_get_info");
return -1;
}
/* Simple data types can be printed directly. */
printf("rinfo_radid = %d\n", radinfo.rinfo_radid);
printf("rinfo_state = %d\n", radinfo.rinfo_state);
printf("rinfo_physmem = 0x%lx pages\n", radinfo.rinfo_physmem);
printf("rinfo_freemem = 0x%lx pages\n", radinfo.rinfo_freemem);
printf("\ncpuset members: ");
/* Complex datatypes (cpuset) need to be enumerated. */
while (1) {
cpuid_t id;
int flags = SET_CURSOR_CONSUME;
cpu_cursor_t cpu_cursor = SET_CURSOR_INIT;
id = cpu_foreach(radinfo.rinfo_cpuset, flags, &cpu_cursor);
if (id == CPU_NONE) {
printf("\n");
break;
} else {
printf("%3d ", id);
}
}
/* Destroy cpuset */
cpusetdestroy(&radinfo.rinfo_cpuset);
return 0;
}
SEE ALSO
Functions: cpu_foreach(3), cpusetcreate(3), nloc(3), numa_intro(3)
Files: numa_types(4)
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