table of contents
CPUSET(9) | Kernel Developer's Manual | CPUSET(9) |
NAME¶
cpuset(9)
—
CPUSET_T_INITIALIZER
,
CPUSET_FSET
, CPU_CLR
,
CPU_COPY
, CPU_ISSET
,
CPU_SET
, CPU_ZERO
,
CPU_FILL
, CPU_SETOF
,
CPU_EMPTY
, CPU_ISFULLSET
,
CPU_FFS
, CPU_COUNT
,
CPU_SUBSET
, CPU_OVERLAP
,
CPU_CMP
, CPU_OR
,
CPU_AND
, CPU_NAND
,
CPU_CLR_ATOMIC
,
CPU_SET_ATOMIC
,
CPU_SET_ATOMIC_ACQ
,
CPU_AND_ATOMIC
, CPU_OR_ATOMIC
,
CPU_COPY_STORE_REL
—
SYNOPSIS¶
#include <sys/_cpuset.h>
#include <sys/cpuset.h>
CPUSET_T_INITIALIZER
(ARRAY_CONTENTS);
CPUSET_FSET
CPU_CLR
(size_t
cpu_idx, cpuset_t
*cpuset);
CPU_COPY
(cpuset_t
*from, cpuset_t
*to);
bool
CPU_ISSET
(size_t
cpu_idx, cpuset_t
*cpuset);
CPU_SET
(size_t
cpu_idx, cpuset_t
*cpuset);
CPU_ZERO
(cpuset_t
*cpuset);
CPU_FILL
(cpuset_t
*cpuset);
CPU_SETOF
(size_t
cpu_idx, cpuset_t
*cpuset);
bool
CPU_EMPTY
(cpuset_t
*cpuset);
bool
CPU_ISFULLSET
(cpuset_t
*cpuset);
int
CPU_FFS
(cpuset_t
*cpuset);
int
CPU_COUNT
(cpuset_t
*cpuset);
bool
CPU_SUBSET
(cpuset_t
*haystack, cpuset_t
*needle);
bool
CPU_OVERLAP
(cpuset_t
*cpuset1, cpuset_t
*cpuset2);
bool
CPU_CMP
(cpuset_t
*cpuset1, cpuset_t
*cpuset2);
CPU_OR
(cpuset_t
*dst, cpuset_t
*src);
CPU_AND
(cpuset_t
*dst, cpuset_t
*src);
CPU_NAND
(cpuset_t
*dst, cpuset_t
*src);
CPU_CLR_ATOMIC
(size_t
cpu_idx, cpuset_t
*cpuset);
CPU_SET_ATOMIC
(size_t
cpu_idx, cpuset_t
*cpuset);
CPU_SET_ATOMIC_ACQ
(size_t
cpu_idx, cpuset_t
*cpuset);
CPU_AND_ATOMIC
(cpuset_t
*dst, cpuset_t
*src);
CPU_OR_ATOMIC
(cpuset_t
*dst, cpuset_t
*src);
CPU_COPY_STORE_REL
(cpuset_t
*from, cpuset_t
*to);
DESCRIPTION¶
Thecpuset(9)
family of macros provide a flexible and
efficient CPU set implementation, backed by the bitset(9)
macros. Each CPU is represented by a single bit. The maximum number of CPUs
representable by cpuset_t is
MAXCPU. Individual CPUs in cpusets are referenced with
indices zero through MAXCPU - 1.
The CPUSET_T_INITIALIZER
() macro allows
one to initialize a cpuset_t with a compile time
literal value.
The CPUSET_FSET
() macro defines a compile
time literal, usable by CPUSET_T_INITIALIZER
(),
representing a full cpuset (all CPUs present). For examples of
CPUSET_T_INITIALIZER
() and
CPUSET_FSET
() usage, see the
CPUSET_T_INITIALIZER
EXAMPLE section.
The CPU_CLR
() macro removes CPU
cpu_idx from the cpuset pointed to by
cpuset. The CPU_CLR_ATOMIC
()
macro is identical, but the bit representing the CPU is cleared with atomic
machine instructions.
The CPU_COPY
() macro copies the contents
of the cpuset from to the cpuset
to. CPU_COPY_STORE_REL
() is
similar, but copies component machine words from from
and writes them to to with atomic store with release
semantics. (That is, if to is composed of multiple
machine words, CPU_COPY_STORE_REL
() performs
multiple individually atomic operations.)
The CPU_SET
() macro adds CPU
cpu_idx to the cpuset pointed to by
cpuset, if it is not already present. The
CPU_SET_ATOMIC
() macro is identical, but the bit
representing the CPU is set with atomic machine instructions. The
CPU_SET_ATOMIC_ACQ
() macro sets the bit representing
the CPU with atomic acquire semantics.
The CPU_ZERO
() macro removes all CPUs from
cpuset.
The CPU_FILL
() macro adds all CPUs to
cpuset.
The CPU_SETOF
() macro removes all CPUs in
cpuset before adding only CPU
cpu_idx.
The CPU_EMPTY
() macro returns
true
if cpuset is empty.
The CPU_ISFULLSET
() macro returns
true
if cpuset is full (the
set of all CPUs).
The CPU_FFS
() macro returns the 1-index of
the first (lowest) CPU in cpuset, or zero if
cpuset is empty. Like with ffs(3),
to use the non-zero result of CPU_FFS
() as a
cpu_idx index parameter to any other
cpuset(9)
macro, you must subtract one from the
result.
The CPU_COUNT
() macro returns the total
number of CPUs in cpuset.
The CPU_SUBSET
() macro returns
true
if needle is a subset of
haystack.
The CPU_OVERLAP
() macro returns
true
if cpuset1 and
cpuset2 have any common CPUs. (That is, if
cpuset1 AND cpuset2 is not the
empty set.)
The CPU_CMP
() macro returns
true
if cpuset1 is NOT equal
to cpuset2.
The CPU_OR
() macro adds CPUs present in
src to dst. (It is the
cpuset(9)
equivalent of the scalar:
dst |= src.)
CPU_OR_ATOMIC
() is similar, but sets the bits
representing CPUs in the component machine words in
dst with atomic machine instructions. (That is, if
dst is composed of multiple machine words,
CPU_OR_ATOMIC
() performs multiple individually
atomic operations.)
The CPU_AND
() macro removes CPUs absent
from src from dst. (It is the
cpuset(9)
equivalent of the scalar:
dst &= src.)
CPU_AND_ATOMIC
() is similar, with the same atomic
semantics as CPU_OR_ATOMIC
().
The CPU_NAND
() macro removes CPUs in
src from dst. (It is the
cpuset(9)
equivalent of the scalar:
dst &= ~ src.)
CPUSET_T_INITIALIZER EXAMPLE¶
cpuset_t myset; /* Initialize myset to filled (all CPUs) */ myset = CPUSET_T_INITIALIZER(CPUSET_FSET); /* Initialize myset to only the lowest CPU */ myset = CPUSET_T_INITIALIZER(0x1);
SEE ALSO¶
cpuset(1), cpuset(2), bitset(9)HISTORY¶
<sys/cpuset.h>
first appeared in
FreeBSD 7.1, released in January 2009, and in
FreeBSD 8.0, released in November 2009.
This manual page first appeared in FreeBSD 11.0.
AUTHORS¶
Thecpuset(9)
macros were written by
Jeff Roberson
<jeff@FreeBSD.org>.
This manual page was written by Conrad Meyer
<cem@FreeBSD.org>.
CAVEATS¶
Unlike every other reference to individual set members, which are zero-indexed,CPU_FFS
() returns a one-indexed result (or zero if the
cpuset is empty).
August 1, 2016 | Linux 4.9.0-9-amd64 |