xref: /freebsd/share/man/man9/BUS_GET_CPUS.9 (revision d0b2dbfa0ecf2bbc9709efc5e20baf8e4b44bbbf)
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26.\" $FreeBSD$
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28.Dd March 1, 2016
29.Dt BUS_GET_CPUS 9
30.Os
31.Sh NAME
32.Nm BUS_GET_CPUS ,
33.Nm bus_get_cpus
34.Nd "request a set of device-specific CPUs"
35.Sh SYNOPSIS
36.In sys/param.h
37.In sys/bus.h
38.In sys/cpuset.h
39.Ft int
40.Fo BUS_GET_CPUS
41.Fa "device_t dev" "device_t child" "enum cpu_sets op" "size_t setsize"
42.Fa "cpuset_t *cpuset"
43.Fc
44.Ft int
45.Fo bus_get_cpus
46.Fa "device_t dev" "enum cpu_sets op" "size_t setsize" "cpuset_t *cpuset"
47.Fc
48.Sh DESCRIPTION
49The
50.Fn BUS_GET_CPUS
51method queries the parent bus device for a set of device-specific CPUs.
52The
53.Fa op
54argument specifies which set of CPUs to retrieve.
55If successful,
56the requested set of CPUs are returned in
57.Fa cpuset .
58The
59.Fa setsize
60argument specifies the size in bytes of the set passed in
61.Fa cpuset .
62.Pp
63.Fn BUS_GET_CPUS
64supports querying different types of CPU sets via the
65.Fa op argument.
66Not all set types are supported for every device.
67If a set type is not supported,
68.Fn BUS_GET_CPUS
69fails with
70.Er EINVAL .
71These set types are supported:
72.Bl -tag -width ".Dv LOCAL_CPUS"
73.It Dv LOCAL_CPUS
74The set of CPUs that are local to the device.
75If a device is closer to a specific memory domain in a non-uniform memory
76architecture system
77.Pq NUMA ,
78this will return the set of CPUs in that memory domain.
79.It Dv INTR_CPUS
80The preferred set of CPUs that this device should use for device interrupts.
81This set type must be supported by all bus drivers.
82.El
83.Pp
84The
85.Fn bus_get_cpus
86function is a simple wrapper around
87.Fn BUS_GET_CPUS .
88.Sh RETURN VALUES
89Zero is returned on success, otherwise an appropriate error is returned.
90.Sh SEE ALSO
91.Xr cpuset 2 ,
92.Xr BUS_BIND_INTR 9 ,
93.Xr device 9
94.Sh HISTORY
95The
96.Fn BUS_GET_CPUS
97method and
98.Fn bus_get_cpus
99function first appeared in
100.Fx 11.0 .
101