freebsd-dev/lib/libpmc/pmc_set.3

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.\" Copyright (c) 2007 Joseph Koshy. All rights reserved.
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.\" $FreeBSD$
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.Dd November 25, 2007
.Dt PMC_SET 3
.Os
.Sh NAME
.Nm pmc_set
.Nd set the reload count of a sampling PMC
.Sh LIBRARY
.Lb libpmc
.Sh SYNOPSIS
.In pmc.h
.Ft int
.Fn pmc_set "pmc_id_t pmc" "pmc_value_t value"
.Sh DESCRIPTION
Function
.Fn pmc_set
is used to set the reload value of sampling PMCs.
Argument
.Fa pmc
specified the handle a previously allocate sampling mode PMC.
Argument
.Fa value
specifies the reload count.
.Pp
Sampling PMCs will interrupt the CPU after the number of
hardware events specified by the reload count are seen.
After the sampling interrupt is processed the underlying hardware will
be reloaded with the specified count and the hardware
automatically restarted by
.Xr hwpmc 4 .
.Pp
Function
.Fn pmc_set
should be called on PMC in a quiescent state.
.Sh RETURN VALUES
.Rv -std pmc_set
.Sh ERRORS
A call to
.Fn pmc_set
may fail with the following errors:
.Bl -tag -width Er
.It Bq Er EINVAL
The current process did not own a PMC with the specified handle.
.It Bq Er EBUSY
The specified PMC was already running.
.El
.Sh SEE ALSO
.Xr pmc 3 ,
.Xr hwpmc 4