PMC_ENABLE(3) BSD Library Functions Manual PMC_ENABLE(3)NAME
pmc_disable, pmc_enable — administrative control of hardware performance
counters
LIBRARY
Performance Counters Library (libpmc, -lpmc)
SYNOPSIS
#include <pmc.h>
int
pmc_disable(int cpu, int pmc);
int
pmc_enable(int cpu, int pmc);
DESCRIPTION
These functions allow specific hardware performance monitoring counters
in a system to be disabled and enabled administratively. The hardware
performance counters available on each CPU are numbered using small non-
negative integers, in a system dependent manner. Disabled counters will
not be available to applications for use.
The invoking process needs to have the PRIV_PMC_MANAGE privilege to per‐
form these operations.
Function pmc_disable() disables the hardware counter numbered by argument
pmc on CPU number cpu.
Function pmc_enable() enables the hardware counter numbered by argument
pmc on CPU number cpu.
IMPLEMENTATION NOTES
Hardware PMCs that are currently in use by applications cannot be dis‐
abled. Allocation of a process scope software PMC marks all hardware
PMCs in the system with the same pmc number as being in-use.
RETURN VALUES
Upon successful completion, the value 0 is returned; otherwise the
value -1 is returned and the global variable errno is set to indicate the
error.
ERRORS
A call to these functions may fail with the following errors:
[EBUSY] Function pmc_disable() specified a hardware PMC is
currently in use.
[EINVAL] Arguments cpu or pmc were invalid.
[ENXIO] Argument cpu specified a disabled or absent CPU.
[EPERM] The current process lacks sufficient privilege to per‐
form this operation.
SEE ALSOpmc(3), pmc_cpuinfo(3), pmc_pmcinfo(3), hwpmc(4), pmccontrol(8),
priv_check(9)BSD September 22, 2008 BSD
