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 hard-
ware performance counters available on each CPU are numbered using small non-negative integers, in a system dependent manner. Disabled coun-
ters will not be available to applications for use.
The invoking process needs to have the PRIV_PMC_MANAGE privilege to perform 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 disabled. 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 perform this operation.
SEE ALSO
pmc(3), pmc_cpuinfo(3), pmc_pmcinfo(3), hwpmc(4), pmccontrol(8), priv_check(9)
BSD
September 22, 2008 BSD
