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 - 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
-nosplit 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).