NAME

pmc_get_msr —

x86 architecture-specific PMC operations

LIBRARY

Performance Counters Library (libpmc, -lpmc)

SYNOPSIS

#include <pmc.h>

int
pmc_get_msr(pmc_id_t pmc, uint32_t *msr);

DESCRIPTION

The function pmc_get_msr() returns the processor model specific register number associated with a PMC for subsequent use with RDPMC instructions. Argument pmc specifies a process scope counting PMC. The function will write the model specific register number associated with the PMC to the location pointed to by argument msr.

After successful completion of this function, applications can directly read the contents of PMC hardware using RDPMC instructions.

RETURN VALUES

The pmc_get_msr() function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indicate the error.

ERRORS

A call to pmc_get_msr() may fail with the following errors:

[EINVAL]: The PMC handle specified was invalid.
[EINVAL]: The PMC specified did not have process scope or counting mode.
[EINVAL]: The PMC specified was allocated with the PMC_F_DESCENDANTS flag.
[EINVAL]: The specified PMC is already attached to target processes other than the owner.
[ENOSYS]: The underlying hardware does not support an RDPMC instruction.