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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_ORNOT,   CPU_AND,   CPU_ANDNOT,   CPU_XOR,	 CPU_CLR_ATOMIC,
     CPU_TEST_CLR_ATOMIC,	    CPU_SET_ATOMIC,	     CPU_SET_ATOMIC_ACQ,
     CPU_TEST_SET_ATOMIC, 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 *src1, cpuset_t *src2);

     CPU_ORNOT(cpuset_t *dst, cpuset_t *src1, cpuset_t *src2);

     CPU_AND(cpuset_t *dst, cpuset_t *src1, cpuset_t *src2);

     CPU_ANDNOT(cpuset_t *dst, cpuset_t *src1, cpuset_t *src2);

     CPU_XOR(cpuset_t *dst, cpuset_t *src1, cpuset_t *src2);

     CPU_CLR_ATOMIC(size_t cpu_idx, cpuset_t *cpuset);

     CPU_TEST_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_TEST_SET_ATOMIC(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 im-
     plementation, backed by the bitset(9) macros.  Each CPU is represented by a
     single  bit.   The  maximum  number  of  CPUs  representable by cpuset_t is
     CPU_SETSIZE.  Individual CPUs in cpusets are referenced with  indices  zero
     through CPU_SETSIZE - 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_TEST_CLR_ATOMIC() macro atomically clears the bit representing the  CPU
     and returns whether it was set.

     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_TEST_SET_ATOMIC() macro atomically sets the bit
     representing the CPU and returns whether it was set.

     The CPU_ISSET() macro returns true if CPU cpu_idx is a member of the cpuset
     pointed to by cpuset.

     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 ma-
     chine words, CPU_OR_ATOMIC() performs multiple individually  atomic  opera-
     tions.)

     The  CPU_ORNOT()  macro  add  CPUs not in src to dst.  (It is the cpuset(9)
     equivalent of the scalar: dst |= ~ src.)

     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 simi-
     lar, with the same atomic semantics as CPU_OR_ATOMIC().

     The  CPU_ANDNOT() 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-in-
     dexed, CPU_FFS() returns a one-indexed result (or zero  if  the  cpuset  is
     empty).

FreeBSD ports 15.quarterly	 August 7, 2025 		       CPUSET(9)

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