1.\" Copyright (c) 2007-2008 Joseph Koshy. All rights reserved. 2.\" 3.\" Redistribution and use in source and binary forms, with or without 4.\" modification, are permitted provided that the following conditions 5.\" are met: 6.\" 1. Redistributions of source code must retain the above copyright 7.\" notice, this list of conditions and the following disclaimer. 8.\" 2. Redistributions in binary form must reproduce the above copyright 9.\" notice, this list of conditions and the following disclaimer in the 10.\" documentation and/or other materials provided with the distribution. 11.\" 12.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 13.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 14.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 15.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 16.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 17.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 18.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 19.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 20.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 21.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 22.\" SUCH DAMAGE. 23.\" 24.Dd September 22, 2008 25.Dt PMC_ENABLE 3 26.Os 27.Sh NAME 28.Nm pmc_disable , 29.Nm pmc_enable 30.Nd administrative control of hardware performance counters 31.Sh LIBRARY 32.Lb libpmc 33.Sh SYNOPSIS 34.In pmc.h 35.Ft int 36.Fn pmc_disable "int cpu" "int pmc" 37.Ft int 38.Fn pmc_enable "int cpu" "int pmc" 39.Sh DESCRIPTION 40These functions allow specific hardware performance monitoring 41counters in a system to be disabled and enabled administratively. 42The hardware performance counters available on each CPU are numbered 43using small non-negative integers, in a system dependent manner. 44Disabled counters will not be available to applications for use. 45.Pp 46The invoking process needs to have the 47.Dv PRIV_PMC_MANAGE 48privilege to perform these operations. 49.Pp 50Function 51.Fn pmc_disable 52disables the hardware counter numbered by argument 53.Fa pmc 54on CPU number 55.Fa cpu . 56.Pp 57Function 58.Fn pmc_enable 59enables the hardware counter numbered by argument 60.Fa pmc 61on CPU number 62.Fa cpu . 63.Sh IMPLEMENTATION NOTES 64Hardware PMCs that are currently in use by applications cannot be 65disabled. 66Allocation of a process scope software PMC marks all 67hardware PMCs in the system with the same pmc number as being in-use. 68.Sh RETURN VALUES 69.Rv -std 70.Sh ERRORS 71A call to these functions may fail with the following errors: 72.Bl -tag -width Er 73.It Bq Er EBUSY 74Function 75.Fn pmc_disable 76specified a hardware PMC is currently in use. 77.It Bq Er EINVAL 78Arguments 79.Fa cpu 80or 81.Fa pmc 82were invalid. 83.It Bq Er ENXIO 84Argument 85.Fa cpu 86specified a disabled or absent CPU. 87.It Bq Er EPERM 88The current process lacks sufficient privilege to perform this 89operation. 90.El 91.Sh SEE ALSO 92.Xr pmc 3 , 93.Xr pmc_cpuinfo 3 , 94.Xr pmc_pmcinfo 3 , 95.Xr hwpmc 4 , 96.Xr pmccontrol 8 , 97.Xr priv_check 9 98