xref: /freebsd/share/man/man9/BUS_GET_CPUS.9 (revision 4f8f43b06ed07e96a250855488cc531799d5b78f)
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26.Dd March 1, 2016
27.Dt BUS_GET_CPUS 9
28.Os
29.Sh NAME
30.Nm BUS_GET_CPUS ,
31.Nm bus_get_cpus
32.Nd "request a set of device-specific CPUs"
33.Sh SYNOPSIS
34.In sys/param.h
35.In sys/bus.h
36.In sys/cpuset.h
37.Ft int
38.Fo BUS_GET_CPUS
39.Fa "device_t dev" "device_t child" "enum cpu_sets op" "size_t setsize"
40.Fa "cpuset_t *cpuset"
41.Fc
42.Ft int
43.Fo bus_get_cpus
44.Fa "device_t dev" "enum cpu_sets op" "size_t setsize" "cpuset_t *cpuset"
45.Fc
46.Sh DESCRIPTION
47The
48.Fn BUS_GET_CPUS
49method queries the parent bus device for a set of device-specific CPUs.
50The
51.Fa op
52argument specifies which set of CPUs to retrieve.
53If successful,
54the requested set of CPUs are returned in
55.Fa cpuset .
56The
57.Fa setsize
58argument specifies the size in bytes of the set passed in
59.Fa cpuset .
60.Pp
61.Fn BUS_GET_CPUS
62supports querying different types of CPU sets via the
63.Fa op argument.
64Not all set types are supported for every device.
65If a set type is not supported,
66.Fn BUS_GET_CPUS
67fails with
68.Er EINVAL .
69These set types are supported:
70.Bl -tag -width ".Dv LOCAL_CPUS"
71.It Dv LOCAL_CPUS
72The set of CPUs that are local to the device.
73If a device is closer to a specific memory domain in a non-uniform memory
74architecture system
75.Pq NUMA ,
76this will return the set of CPUs in that memory domain.
77.It Dv INTR_CPUS
78The preferred set of CPUs that this device should use for device interrupts.
79This set type must be supported by all bus drivers.
80.El
81.Pp
82The
83.Fn bus_get_cpus
84function is a simple wrapper around
85.Fn BUS_GET_CPUS .
86.Sh RETURN VALUES
87Zero is returned on success, otherwise an appropriate error is returned.
88.Sh SEE ALSO
89.Xr cpuset 2 ,
90.Xr BUS_BIND_INTR 9 ,
91.Xr device 9
92.Sh HISTORY
93The
94.Fn BUS_GET_CPUS
95method and
96.Fn bus_get_cpus
97function first appeared in
98.Fx 11.0 .
99