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 — cpuset manipulation macros

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

The cpuset(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

The cpuset(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).