pmc_attach(3) [freebsd man page]
PMC_ATTACH(3) BSD Library Functions Manual PMC_ATTACH(3) NAME
pmc_attach, pmc_detach -- attaching and detaching process scope PMCs to target processes LIBRARY
Performance Counters Library (libpmc, -lpmc) SYNOPSIS
#include <pmc.h> int pmc_attach(pmc_id_t pmcid, pid_t pid); int pmc_detach(pmc_id_t pmcid, pid_t pid); DESCRIPTION
These functions control the set of target processes tracked by a process scope PMC. Function pmc_attach() is used to attach a process scope PMC specified by argument pmcid to a target process specified by argument pid. Argu- ment pid may be zero to denote the current process. If the PMC was allocated with modifier PMC_F_DESCENDANTS, the PMC will additionally attach to current and future descendents of the specified target process. The PMC should be in a quiescent state (i.e., not running). Function pmc_detach() is used to detach a process scope PMC specified by argument pmcid from a process specified by argument pid. Argument pid may be zero to denote the current process. 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 function pmc_attach() may fail with the following errors: [EBUSY] Argument pmcid specified a PMC that was not in a quiescent state. [EBUSY] The target process specified by function pmc_attach is being tracked by another process scope PMC that uses the same PMC hardware resources. [EEXIST] The target process is already being tracked by the specified PMC. [EINVAL] Argument pmcid specified a PMC with system scope. [EINVAL] Argument pid specified an illegal process id. [EINVAL] The current process does not own a PMC with the handle specified in argument pmcid. [EPERM] The caller lacked the privilege needed to attach PMCs to the specified target process. [EPERM] (i386 and amd64 architectures) The PMC specified by argument pmcid has been setup to allow the use of the RDPMC instruc- tion for self measurement. [ESRCH] The current process does not own any PMCs. [ESRCH] The process specified by argument pid did not exist. A call to function pmc_detach() may fail with the following errors: [EINVAL] Argument pmcid specified a PMC with system scope. [EINVAL] Argument pid specified an illegal process id. [EINVAL] The current process does not own a PMC with the handle specified in argument pmcid. [EINVAL] The specified PMC was not attached to the target process. [ESRCH] The current process does not own any PMCs. [ESRCH] The process specified by argument pid is not being monitored by hwpmc(4). [ESRCH] The process specified by argument pid did not exist. SEE ALSO
pmc(3), pmc_start(3), pmc_stop(3), hwpmc(4) BSD
November 25, 2007 BSD
Check Out this Related Man Page
PMC_CAPABILITIES(3) BSD 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 capabili- ties 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 coun- ters 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) BSD
September 22, 2008 BSD