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PMC_CAPABILITIES(3) FreeBSD Library Functions Manual PMC_CAPABILITIES(3)
NAME
pmc_capabilities, pmc_cpuinfo, pmc_ncpu, pmc_npmc, pmc_pmcinfo, pmc_width
- retrieve information about performance monitoring counters
LIBRARY
Performance Counters Library (libpmc, -lpmc)
SYNOPSIS
#include <pmc.h>
int
pmc_capabilities(pmc_id_t pmc, uint32_t *caps);
int
pmc_cpuinfo(const struct pmc_cpuinfo **cpu_info);
int
pmc_ncpu(void);
int
pmc_npmc(int cpu);
int
pmc_pmcinfo(int cpu, struct pmc_pmcinfo **pmc_info);
int
pmc_width(pmc_id_t pmc, uint32_t *width);
DESCRIPTION
These functions retrieve information about performance monitoring
hardware.
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
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.
RETURN VALUES
Functions pmc_ncpu() and pmc_npmc() returns a positive integer if
successful; otherwise the value -1 is returned and the global variable
errno is set to indicate the error.
Functions pmc_capabilities(), pmc_cpuinfo(), pmc_pmcinfo() and
pmc_width() return 0 if successful; otherwise the value -1 is returned
and the global variable errno is set to indicate the error.
ERRORS
A call to function pmc_capabilities() may fail with the following errors:
[EINVAL] The argument to the function was invalid.
Calls to functions pmc_cpuinfo(), pmc_ncpu() and pmc_npmc() may fail with
the following errors:
[ENXIO] A prior call to pmc_init() to initialize the PMC
library had failed.
A call to function pmc_pmcinfo() may fail with the following errors:
[EINVAL] The argument cpu was invalid.
[ENXIO] The argument cpu specified a disabled or absent CPU.
A call to function pmc_width() may fail with the following errors:
[EINVAL] The argument to the function was invalid.
SEE ALSO
pmc(3), pmc_allocate(3), pmc_get_driver_stats(3),
pmc_name_of_capability(3), pmc_name_of_class(3), pmc_name_of_cputype(3),
pmc_name_of_event(3), pmc_name_of_mode(3), hwpmc(4)
FreeBSD 14.0-RELEASE-p11 September 22, 2008 FreeBSD 14.0-RELEASE-p11