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PMC_ENABLE(3) FreeBSD 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 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) FreeBSD 14.1-RELEASE-p8 September 22, 2008 FreeBSD 14.1-RELEASE-p8