1 files changed, 84 insertions, 0 deletions
diff --git a/lib/libpmc/pmc_read.3 b/lib/libpmc/pmc_read.3
new file mode 100644
index 0000000..d091716
--- /dev/null
+++ b/lib/libpmc/pmc_read.3
@@ -0,0 +1,84 @@
+.\" Copyright (c) 2007 Joseph Koshy.  All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\"
+.\" This software is provided by Joseph Koshy ``as is'' and
+.\" any express or implied warranties, including, but not limited to, the
+.\" implied warranties of merchantability and fitness for a particular purpose
+.\" are disclaimed.  in no event shall Joseph Koshy be liable
+.\" for any direct, indirect, incidental, special, exemplary, or consequential
+.\" damages (including, but not limited to, procurement of substitute goods
+.\" or services; loss of use, data, or profits; or business interruption)
+.\" however caused and on any theory of liability, whether in contract, strict
+.\" liability, or tort (including negligence or otherwise) arising in any way
+.\" out of the use of this software, even if advised of the possibility of
+.\" such damage.
+.\"
+.\" $FreeBSD$
+.\"
+.Dd November 25, 2007
+.Dt PMC_READ 3
+.Os
+.Sh NAME
+.Nm pmc_read ,
+.Nm pmc_rw ,
+.Nm pmc_write ,
+.Nd read and write hardware performance counters
+.Sh LIBRARY
+.Lb libpmc
+.Sh SYNOPSIS
+.In pmc.h
+.Ft int
+.Fn pmc_read "pmc_id_t pmc" "pmc_value_t *value"
+.Ft int
+.Fn pmc_rw "pmc_id_t pmc" "pmc_value_t newvalue" "pmc_value_t *oldvaluep"
+.Ft int
+.Fn pmc_write "pmc_id_t pmc" "pmc_value_t value"
+.Sh DESCRIPTION
+These functions read and write the current value of a PMC.
+.Pp
+Function
+.Fn pmc_read
+will read the current value of the PMC specified by argument
+.Fa pmc
+and write it to the location specified by argument
+.Fa value .
+.Pp
+Function
+.Fn pmc_write
+will set the current value of the PMC specified by argument
+.Fa pmc
+to the value specified by argument
+.Fa value .
+.Pp
+Function
+.Fn pmc_rw
+combines a read and a write into a single atomic operation.
+.Pp
+For write operations the PMC should be a quiescent state.
+.Sh RETURN VALUES
+.Rv -std
+.Sh ERRORS
+A call to these functions may fail with the following errors:
+.Bl -tag -width Er
+.It Bq Er EBUSY
+A write operation specified a currently running PMC.
+.It Bq Er EINVAL
+Argument
+.Fa pmc
+specified a PMC not in a readable state.
+.It Bq Er EINVAL
+The PMC specified by argument
+.Fa pmc
+was not owned by the current process.
+.El
+.Sh SEE ALSO
+.Xr pmc 3 ,
+.Xr hwpmc 4