PMC_READ(3) BSD Library Functions Manual PMC_READ(3)
pmc_read, pmc_rw, pmc_write, -- read and write hardware performance counters
Performance Counters Library (libpmc, -lpmc)
pmc_read(pmc_id_t pmc, pmc_value_t *value);
pmc_rw(pmc_id_t pmc, pmc_value_t newvalue, pmc_value_t *oldvaluep);
pmc_write(pmc_id_t pmc, pmc_value_t value);
These functions read and write the current value of a PMC.
Function pmc_read() will read the current value of the PMC specified by argument pmc and write it to the location specified by argument
Function pmc_write() will set the current value of the PMC specified by argument pmc to the value specified by argument value.
Function pmc_rw() combines a read and a write into a single atomic operation.
For write operations the PMC should be a quiescent state.
Upon successful completion, the value 0 is returned; otherwise the value -1 is returned and the global variable errno is set to indicate the
A call to these functions may fail with the following errors:
[EBUSY] A write operation specified a currently running PMC.
[EINVAL] Argument pmc specified a PMC not in a readable state.
[EINVAL] The PMC specified by argument pmc was not owned by the current process.
November 25, 2007 BSD