100 lines
3.0 KiB
Groff
100 lines
3.0 KiB
Groff
.\" Copyright (c) 2007-2008 Joseph Koshy. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" This software is provided by Joseph Koshy ``as is'' and
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.\" any express or implied warranties, including, but not limited to, the
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.\" implied warranties of merchantability and fitness for a particular purpose
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.\" are disclaimed. in no event shall Joseph Koshy be liable
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.\" for any direct, indirect, incidental, special, exemplary, or consequential
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.\" damages (including, but not limited to, procurement of substitute goods
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.\" or services; loss of use, data, or profits; or business interruption)
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.\" however caused and on any theory of liability, whether in contract, strict
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.\" liability, or tort (including negligence or otherwise) arising in any way
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.\" out of the use of this software, even if advised of the possibility of
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.\" such damage.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd September 22, 2008
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.Os
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.Dt PMC_ENABLE 3
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.Sh NAME
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.Nm pmc_disable ,
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.Nm pmc_enable
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.Nd administrative control of hardware performance counters
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.Sh LIBRARY
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.Lb libpmc
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.Sh SYNOPSIS
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.In pmc.h
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.Ft int
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.Fn pmc_disable "int cpu" "int pmc"
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.Ft int
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.Fn pmc_enable "int cpu" "int pmc"
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.Sh DESCRIPTION
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These functions allow specific hardware performance monitoring
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counters in a system to be disabled and enabled administratively.
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The hardware performance counters available on each CPU are numbered
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using small non-negative integers, in a system dependent manner.
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Disabled counters will not be available to applications for use.
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.Pp
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The invoking process needs to have the
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.Dv PRIV_PMC_MANAGE
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privilege to perform these operations.
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.Pp
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Function
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.Fn pmc_disable
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disables the hardware counter numbered by argument
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.Fa pmc
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on CPU number
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.Fa cpu .
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.Pp
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Function
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.Fn pmc_enable
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enables the hardware counter numbered by argument
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.Fa pmc
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on CPU number
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.Fa cpu .
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.Sh IMPLEMENTATION NOTES
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Hardware PMCs that are currently in use by applications cannot be
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disabled.
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Allocation of a process scope software PMC marks all
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hardware PMCs in the system with the same pmc number as being in-use.
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.Sh RETURN VALUES
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.Rv -std
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.Sh ERRORS
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A call to these functions may fail with the following errors:
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.Bl -tag -width Er
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.It Bq Er EBUSY
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Function
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.Fn pmc_disable
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specified a hardware PMC is currently in use.
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.It Bq Er EINVAL
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Arguments
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.Fa cpu
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or
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.Fa pmc
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were invalid.
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.It Bq Er ENXIO
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Argument
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.Fa cpu
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specified a disabled or absent CPU.
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.It Bq Er EPERM
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The current process lacks sufficient privilege to perform this
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operation.
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.El
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.Sh SEE ALSO
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.Xr pmc 3 ,
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.Xr pmc_cpuinfo 3 ,
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.Xr pmc_pmcinfo 3 ,
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.Xr hwpmc 4 ,
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.Xr pmccontrol 8 ,
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.Xr priv_check 9
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