xref: /freebsd/lib/libpmc/pmc_get_msr.3 (revision a0b9e2e854027e6ff61fb075a1309dbc71c42b54)
1.\" Copyright (c) 2007 Joseph Koshy.  All rights reserved.
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24.\" $FreeBSD$
25.\"
26.Dd November 25, 2007
27.Dt PMC_GET_MSR 3
28.Os
29.Sh NAME
30.Nm pmc_get_msr
31.Nd x86 architecture-specific PMC operations
32.Sh LIBRARY
33.Lb libpmc
34.Sh SYNOPSIS
35.In pmc.h
36.Ft int
37.Fn pmc_get_msr "pmc_id_t pmc" "uint32_t *msr"
38.Sh DESCRIPTION
39The function
40.Fn pmc_get_msr
41returns the processor model specific register number associated with
42a PMC for subsequent use with RDPMC instructions.
43Argument
44.Fa pmc
45specifies a process scope counting PMC.
46The function will write the model specific register number associated
47with the PMC to the location pointed to by argument
48.Fa msr .
49.Pp
50After successful completion of this function, applications
51can directly read the contents of PMC hardware using
52RDPMC instructions.
53.Sh RETURN VALUES
54.Rv -std pmc_get_msr
55.Sh ERRORS
56A call to
57.Fn pmc_get_msr
58may fail with the following errors:
59.Bl -tag -width Er
60.It Bq Er EINVAL
61The PMC handle specified was invalid.
62.It Bq Er EINVAL
63The PMC specified did not have process scope or counting mode.
64.It Bq Er EINVAL
65The PMC specified was allocated with the
66.Dv PMC_F_DESCENDANTS
67flag.
68.It Bq Er EINVAL
69The specified PMC is already attached to target processes other
70than the owner.
71.It Bq Er ENOSYS
72The underlying hardware does not support an RDPMC instruction.
73.El
74.Sh SEE ALSO
75.Xr pmc 3 ,
76.Xr hwpmc 4
77