NAME
cpuset_getaffinity,
cpuset_setaffinity —
manage CPU affinity
LIBRARY
library “libc”
SYNOPSIS
#include
<sys/param.h>
#include <sys/cpuset.h>
int
cpuset_getaffinity(cpulevel_t
level, cpuwhich_t
which, id_t id,
size_t setsize,
cpuset_t *mask);
int
cpuset_setaffinity(cpulevel_t
level, cpuwhich_t
which, id_t id,
size_t setsize,
const cpuset_t
*mask);
DESCRIPTION
cpuset_getaffinity()
and cpuset_setaffinity() allow the manipulation of
sets of CPUs available to processes, threads, interrupts, jails and other
resources. These functions may manipulate sets of CPUs that contain many
processes or per-object anonymous masks that effect only a single object.
The valid values for the level and
which arguments are documented in
cpuset(2). These arguments specify which object and which set of the
object we are referring to. Not all possible combinations are valid. For
example, only processes may belong to a numbered set accessed by a
level argument of
CPU_LEVEL_CPUSET. All resources, however, have a
mask which may be manipulated with
CPU_LEVEL_WHICH.
Masks of type
cpuset_t are composed using the
CPU_SET macros. The kernel tolerates large sets as
long as all CPUs specified in the set exist. Sets smaller than the kernel
uses generate an error on calls to
cpuset_getaffinity()
even if the result set would fit within the user supplied set. Calls to
cpuset_setaffinity() tolerate small sets with no
restrictions.
The supplied mask should have a size of
setsize bytes. This size is usually provided by
calling sizeof(mask) which is ultimately determined
by the value of CPU_SETSIZE as defined in
<sys/cpuset.h>.
cpuset_getaffinity()
retrieves the mask from the object specified by level,
which and id and stores it in
the space provided by mask.
cpuset_setaffinity()
attempts to set the mask for the object specified by
level, which and
id to the value in mask.
RETURN VALUES
Upon successful completion, the value 0 is returned; otherwise the value -1 is returned and the global variable errno is set to indicate the error.
ERRORS
The following error codes may be set in errno:
- [
EINVAL] - The level or which argument was not a valid value.
- [
EINVAL] - The mask argument specified when calling
cpuset_setaffinity() was not a valid value. - [
EDEADLK] - The
cpuset_setaffinity() call would leave a thread without a valid CPU to run on because the set does not overlap with the thread's anonymous mask. - [
EFAULT] - The mask pointer passed was invalid.
- [
ESRCH] - The object specified by the id and which arguments could not be found.
- [
ERANGE] - The cpusetsize was either preposterously large or smaller than the kernel set size.
- [
EPERM] - The calling process did not have the credentials required to complete the operation.
- [
ECAPMODE] - The calling process attempted to act on a process other than itself, while in capability mode. See capsicum(4).
SEE ALSO
capsicum(4), cpuset(1), cpuset(2), cpuset_getid(2), cpuset_setid(2), cpuset_getdomain(2), cpuset_setdomain(2), pthread_affinity_np(3), pthread_attr_affinity_np(3), cpuset(9)
HISTORY
The cpuset_getaffinity family of system
calls first appeared in FreeBSD 7.1.
AUTHORS
Jeffrey Roberson <jeff@FreeBSD.org>