xref: /freebsd/share/man/man9/cpuset.9 (revision 349cc55c9796c4596a5b9904cd3281af295f878f)
1.\" Copyright (c) 2015 Conrad Meyer <cem@FreeBSD.org>
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25.\" $FreeBSD$
26.\"
27.Dd December 12, 2019
28.Dt CPUSET 9
29.Os
30.Sh NAME
31.Nm cpuset(9)
32\(em
33.Nm CPUSET_T_INITIALIZER ,
34.Nm CPUSET_FSET ,
35.Nm CPU_CLR ,
36.Nm CPU_COPY ,
37.Nm CPU_ISSET ,
38.Nm CPU_SET ,
39.Nm CPU_ZERO ,
40.Nm CPU_FILL ,
41.Nm CPU_SETOF ,
42.Nm CPU_EMPTY ,
43.Nm CPU_ISFULLSET ,
44.Nm CPU_FFS ,
45.Nm CPU_COUNT ,
46.Nm CPU_SUBSET ,
47.Nm CPU_OVERLAP ,
48.Nm CPU_CMP ,
49.Nm CPU_OR ,
50.Nm CPU_AND ,
51.Nm CPU_ANDNOT ,
52.Nm CPU_XOR ,
53.Nm CPU_CLR_ATOMIC ,
54.Nm CPU_SET_ATOMIC ,
55.Nm CPU_SET_ATOMIC_ACQ ,
56.Nm CPU_AND_ATOMIC ,
57.Nm CPU_OR_ATOMIC ,
58.Nm CPU_COPY_STORE_REL
59.Nd cpuset manipulation macros
60.Sh SYNOPSIS
61.In sys/_cpuset.h
62.In sys/cpuset.h
63.\"
64.Fn CPUSET_T_INITIALIZER "ARRAY_CONTENTS"
65.Vt CPUSET_FSET
66.\"
67.Fn CPU_CLR "size_t cpu_idx" "cpuset_t *cpuset"
68.Fn CPU_COPY "cpuset_t *from" "cpuset_t *to"
69.Ft bool
70.Fn CPU_ISSET "size_t cpu_idx" "cpuset_t *cpuset"
71.Fn CPU_SET "size_t cpu_idx" "cpuset_t *cpuset"
72.Fn CPU_ZERO "cpuset_t *cpuset"
73.Fn CPU_FILL "cpuset_t *cpuset"
74.Fn CPU_SETOF "size_t cpu_idx" "cpuset_t *cpuset"
75.Ft bool
76.Fn CPU_EMPTY "cpuset_t *cpuset"
77.Ft bool
78.Fn CPU_ISFULLSET "cpuset_t *cpuset"
79.Ft int
80.Fn CPU_FFS "cpuset_t *cpuset"
81.Ft int
82.Fn CPU_COUNT "cpuset_t *cpuset"
83.\"
84.Ft bool
85.Fn CPU_SUBSET "cpuset_t *haystack" "cpuset_t *needle"
86.Ft bool
87.Fn CPU_OVERLAP "cpuset_t *cpuset1" "cpuset_t *cpuset2"
88.Ft bool
89.Fn CPU_CMP "cpuset_t *cpuset1" "cpuset_t *cpuset2"
90.Fn CPU_OR "cpuset_t *dst" "cpuset_t *src1" "cpuset_t *src2"
91.Fn CPU_AND "cpuset_t *dst" "cpuset_t *src1" "cpuset_t *src2"
92.Fn CPU_ANDNOT "cpuset_t *dst" "cpuset_t *src1" "cpuset_t *src2"
93.Fn CPU_XOR "cpuset_t *dst" "cpuset_t *src1" "cpuset_t *src2"
94.\"
95.Fn CPU_CLR_ATOMIC "size_t cpu_idx" "cpuset_t *cpuset"
96.Fn CPU_SET_ATOMIC "size_t cpu_idx" "cpuset_t *cpuset"
97.Fn CPU_SET_ATOMIC_ACQ "size_t cpu_idx" "cpuset_t *cpuset"
98.\"
99.Fn CPU_AND_ATOMIC "cpuset_t *dst" "cpuset_t *src"
100.Fn CPU_OR_ATOMIC "cpuset_t *dst" "cpuset_t *src"
101.Fn CPU_COPY_STORE_REL "cpuset_t *from" "cpuset_t *to"
102.Sh DESCRIPTION
103The
104.Nm
105family of macros provide a flexible and efficient CPU set implementation,
106backed by the
107.Xr bitset 9
108macros.
109Each CPU is represented by a single bit.
110The maximum number of CPUs representable by
111.Vt cpuset_t
112is
113.Va MAXCPU .
114Individual CPUs in cpusets are referenced with indices zero through
115.Fa MAXCPU - 1 .
116.Pp
117The
118.Fn CPUSET_T_INITIALIZER
119macro allows one to initialize a
120.Vt cpuset_t
121with a compile time literal value.
122.Pp
123The
124.Fn CPUSET_FSET
125macro defines a compile time literal, usable by
126.Fn CPUSET_T_INITIALIZER ,
127representing a full cpuset (all CPUs present).
128For examples of
129.Fn CPUSET_T_INITIALIZER
130and
131.Fn CPUSET_FSET
132usage, see the
133.Sx CPUSET_T_INITIALIZER EXAMPLE
134section.
135.Pp
136The
137.Fn CPU_CLR
138macro removes CPU
139.Fa cpu_idx
140from the cpuset pointed to by
141.Fa cpuset .
142The
143.Fn CPU_CLR_ATOMIC
144macro is identical, but the bit representing the CPU is cleared with atomic
145machine instructions.
146.Pp
147The
148.Fn CPU_COPY
149macro copies the contents of the cpuset
150.Fa from
151to the cpuset
152.Fa to .
153.Fn CPU_COPY_STORE_REL
154is similar, but copies component machine words from
155.Fa from
156and writes them to
157.Fa to
158with atomic store with release semantics.
159(That is, if
160.Fa to
161is composed of multiple machine words,
162.Fn CPU_COPY_STORE_REL
163performs multiple individually atomic operations.)
164.Pp
165The
166.Fn CPU_SET
167macro adds CPU
168.Fa cpu_idx
169to the cpuset pointed to by
170.Fa cpuset ,
171if it is not already present.
172The
173.Fn CPU_SET_ATOMIC
174macro is identical, but the bit representing the CPU is set with atomic
175machine instructions.
176The
177.Fn CPU_SET_ATOMIC_ACQ
178macro sets the bit representing the CPU with atomic acquire semantics.
179.Pp
180The
181.Fn CPU_ISSET
182macro returns
183.Dv true
184if CPU
185.Fa cpu_idx
186is a member of the cpuset pointed to by
187.Fa cpuset .
188.Pp
189The
190.Fn CPU_ZERO
191macro removes all CPUs from
192.Fa cpuset .
193.Pp
194The
195.Fn CPU_FILL
196macro adds all CPUs to
197.Fa cpuset .
198.Pp
199The
200.Fn CPU_SETOF
201macro removes all CPUs in
202.Fa cpuset
203before adding only CPU
204.Fa cpu_idx .
205.Pp
206The
207.Fn CPU_EMPTY
208macro returns
209.Dv true
210if
211.Fa cpuset
212is empty.
213.Pp
214The
215.Fn CPU_ISFULLSET
216macro returns
217.Dv true
218if
219.Fa cpuset
220is full (the set of all CPUs).
221.Pp
222The
223.Fn CPU_FFS
224macro returns the 1-index of the first (lowest) CPU in
225.Fa cpuset ,
226or zero if
227.Fa cpuset
228is empty.
229Like with
230.Xr ffs 3 ,
231to use the non-zero result of
232.Fn CPU_FFS
233as a
234.Fa cpu_idx
235index parameter to any other
236.Nm
237macro, you must subtract one from the result.
238.Pp
239The
240.Fn CPU_COUNT
241macro returns the total number of CPUs in
242.Fa cpuset .
243.Pp
244The
245.Fn CPU_SUBSET
246macro returns
247.Dv true
248if
249.Fa needle
250is a subset of
251.Fa haystack .
252.Pp
253The
254.Fn CPU_OVERLAP
255macro returns
256.Dv true
257if
258.Fa cpuset1
259and
260.Fa cpuset2
261have any common CPUs.
262(That is, if
263.Fa cpuset1
264AND
265.Fa cpuset2
266is not the empty set.)
267.Pp
268The
269.Fn CPU_CMP
270macro returns
271.Dv true
272if
273.Fa cpuset1
274is NOT equal to
275.Fa cpuset2 .
276.Pp
277The
278.Fn CPU_OR
279macro adds CPUs present in
280.Fa src
281to
282.Fa dst .
283(It is the
284.Nm
285equivalent of the scalar:
286.Fa dst
287|=
288.Fa src . )
289.Fn CPU_OR_ATOMIC
290is similar, but sets the bits representing CPUs in the component machine words
291in
292.Fa dst
293with atomic machine instructions.
294(That is, if
295.Fa dst
296is composed of multiple machine words,
297.Fn CPU_OR_ATOMIC
298performs multiple individually atomic operations.)
299.Pp
300The
301.Fn CPU_AND
302macro removes CPUs absent from
303.Fa src
304from
305.Fa dst .
306(It is the
307.Nm
308equivalent of the scalar:
309.Fa dst
310&=
311.Fa src . )
312.Fn CPU_AND_ATOMIC
313is similar, with the same atomic semantics as
314.Fn CPU_OR_ATOMIC .
315.Pp
316The
317.Fn CPU_ANDNOT
318macro removes CPUs in
319.Fa src
320from
321.Fa dst .
322(It is the
323.Nm
324equivalent of the scalar:
325.Fa dst
326&=
327.Fa ~ src . )
328.Sh CPUSET_T_INITIALIZER EXAMPLE
329.Bd -literal
330cpuset_t myset;
331
332/* Initialize myset to filled (all CPUs) */
333myset = CPUSET_T_INITIALIZER(CPUSET_FSET);
334
335/* Initialize myset to only the lowest CPU */
336myset = CPUSET_T_INITIALIZER(0x1);
337.Ed
338.Sh SEE ALSO
339.Xr cpuset 1 ,
340.Xr cpuset 2 ,
341.Xr bitset 9
342.Sh HISTORY
343.In sys/cpuset.h
344first appeared in
345.Fx 7.1 ,
346released in January 2009, and in
347.Fx 8.0 ,
348released in November 2009.
349.Pp
350This manual page first appeared in
351.Fx 11.0 .
352.Sh AUTHORS
353.An -nosplit
354The
355.Nm
356macros were written by
357.An Jeff Roberson Aq Mt jeff@FreeBSD.org .
358This manual page was written by
359.An Conrad Meyer Aq Mt cem@FreeBSD.org .
360.Sh CAVEATS
361Unlike every other reference to individual set members, which are zero-indexed,
362.Fn CPU_FFS
363returns a one-indexed result (or zero if the cpuset is empty).
364