PAPI_epc(3) PAPI PAPI_epc(3)NAMEPAPI_epc-
Simplified call to get arbitrary events per cycle, real and processor
time.
SYNOPSISDetailed Description
C Interface:
#include <papi.h>
int PAPI_epc( int event, float *rtime, float *ptime, long long
*ref, long long *core, long long *evt, float *epc );
Parameters:
event event code to be measured (0 defaults to PAPI_TOT_INS)
*rtime total realtime since the first call
*ptime total process time since the first call
*ref incremental reference clock cycles since the last call
*core incremental core clock cycles since the last call
*evt total events since the first call
*epc incremental events per cycle since the last call
Return values:
PAPI_EINVAL The counters were already started by something other
than PAPI_epc().
PAPI_ENOEVNT One of the requested events does not exist.
PAPI_ENOMEM Insufficient memory to complete the operation.
The first call to PAPI_epc() will initialize the PAPI High Level
interface, set up the counters to monitor the user specified event,
PAPI_TOT_CYC, and PAPI_REF_CYC (if it exists) and start the counters.
Subsequent calls will read the counters and return total real time,
total process time, total event counts since the start of the
measurement and the core and reference cycle count and EPC rate since
the latest call to PAPI_epc().
A call to PAPI_stop_counters() will stop the counters from running and
then calls such as PAPI_start_counters() or other rate calls can safely
be used.
PAPI_epc can provide a more detailed look at algorithm efficiency in
light of clock variability in modern cpus. MFLOPS is no longer an
adequate description of peak performance if clock rates can arbitrarily
speed up or slow down. By allowing a user specified event and reporting
reference cycles, core cycles and real time, PAPI_epc provides the
information to compute an accurate effective clock rate, and an
accurate measure of computational throughput.
See Also:
PAPI_flips()PAPI_flops()PAPI_ipc()PAPI_stop_counters()Author
Generated automatically by Doxygen for PAPI from the source code.
Version 5.2.0.0 Mon Oct 28 2013 PAPI_epc(3)
