Manual Pages  — PMC_CAPABILITIES

Function pmc_capabilities() retrieves the hardware capabilities of a PMC. Argument pmc is a PMC handle obtained by a prior call to pmc_allocate(). The function sets argument caps to a bit mask of capabilities supported by the PMC denoted by argument pmc. PMC capabilities are described in pmc(3).

Function pmc_cpuinfo() retrieves information about the CPUs in the system. Argument cpu_info will be set to point to an internal structure with information about the system's CPUs. The caller should not free this pointer value. This structure has the following fields:

pm_cputype
	Specifies the CPU type.
pm_ncpu	Specifies the number of CPUs in the system.
pm_npmc	Specifies the number of PMC rows per CPU.
pm_nclass	Specifies the number of distinct classes of PMCs in the system.
pm_classes
	Contains an array of struct pmc_classinfo descriptors describing the properties of each class of PMCs in the system.

Function pmc_ncpu() is a convenience function that returns the maximum CPU number in the system. On systems that support sparsely numbered CPUs, not all CPUs may be physically present. Applications need to be prepared to deal with nonexistent CPUs.

Function pmc_npmc() is a convenience function that returns the number of PMCs available in the CPU specified by argument cpu.

Function pmc_pmcinfo() returns information about the current state of the PMC hardware in the CPU specified by argument cpu. The location specified by argument pmc_info is set to point an array of struct pmc_info structures each describing the state of one PMC in the CPU. These structure contain the following fields:

pm_name	A human readable name for the PMC.
pm_class	The PMC class for the PMC.
pm_enabled	Non-zero if the PMC is enabled.
pm_rowdisp	The disposition of the PMC row for this PMC. Row dispositions are documented in hwpmc(4).
pm_ownerpid
	If the hardware is in use, the process id of the owner of the PMC.
pm_mode	The PMC mode as described in pmc(3).
pm_event	If the hardware is in use, the PMC event being measured.
pm_flags	If the hardware is in use, the flags associated with the PMC.
pm_reloadcount
	For sampling PMCs, the reload count associated with the PMC.

Function pmc_width() is used to retrieve the width in bits of the hardware counters associated with a PMC. Argument pmc is a PMC handle obtained by a prior call to pmc_allocate(). The function sets the location pointed to by argument width to the width of the physical counters associated with PMC pmc.