xref: /freebsd/share/man/man9/BUS_GET_CPUS.9 (revision 8ef24a0d4b28fe230e20637f56869cc4148cd2ca)
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27.\" $FreeBSD$
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29.Dd March 1, 2016
30.Dt BUS_GET_CPUS 9
31.Os
32.Sh NAME
33.Nm BUS_GET_CPUS ,
34.Nm bus_get_cpus
35.Nd "request a set of device-specific CPUs"
36.Sh SYNOPSIS
37.In sys/param.h
38.In sys/bus.h
39.In sys/cpuset.h
40.Ft int
41.Fo BUS_GET_CPUS
42.Fa "device_t dev" "device_t child" "enum cpu_sets op" "size_t setsize"
43.Fa "cpuset_t *cpuset"
44.Fc
45.Ft int
46.Fo bus_get_cpus
47.Fa "device_t dev" "enum cpu_sets op" "size_t setsize" "cpuset_t *cpuset"
48.Fc
49.Sh DESCRIPTION
50The
51.Fn BUS_GET_CPUS
52method queries the parent bus device for a set of device-specific CPUs.
53The
54.Fa op
55argument specifies which set of CPUs to retrieve.
56If successful,
57the requested set of CPUs are returned in
58.Fa cpuset .
59The
60.Fa setsize
61argument specifies the size in bytes of the set passed in
62.Fa cpuset .
63.Pp
64.Fn BUS_GET_CPUS
65supports querying different types of CPU sets via the the
66.Fa op argument.
67Not all set types are supported for every device.
68If a set type is not supported,
69.Fn BUS_GET_CPUS
70fails with
71.Er EINVAL .
72These set types are supported:
73.Bl -tag -width ".Dv LOCAL_CPUS"
74.It Dv LOCAL_CPUS
75The set of CPUs that are local to the device.
76If a device is closer to a specific memory domain in a non-uniform memory
77architecture system
78.Pq NUMA ,
79this will return the set of CPUs in that memory domain.
80.It Dv INTR_CPUS
81The preferred set of CPUs that this device should use for device interrupts.
82This set type must be supported by all bus drivers.
83.El
84.Pp
85The
86.Fn bus_get_cpus
87function is a simple wrapper around
88.Fn BUS_GET_CPUS .
89.Sh RETURN VALUES
90Zero is returned on success, otherwise an appropriate error is returned.
91.Sh SEE ALSO
92.Xr cpuset 2 ,
93.Xr BUS_BIND_INTR 9 ,
94.Xr device 9
95.Sh HISTORY
96The
97.Fn BUS_GET_CPUS
98method and
99.Fn bus_get_cpus
100function first appeared in
101.Fx 11.0 .
102