PAPI_epc(3)

📦
version 7.2.0 · 8 versions
, in nixos 26.05, nixpkgs unstable, opensuse-leap 16.0, ubuntu resolute, ubuntu stonking

💖 NAME 💖

Okay bestie, welcome to PAPI_epc(3) — the manual page for PAPI_epc, aka Simplified call to get arbitrary events per cycle, real and processor time. That's the whole name vibe. 💅

✨ SYNOPSIS ✨

The synopsis is giving “see the C interface below” energy — keep scrolling, babe. 👇

🎀 Detailed 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 — realtime since the latest call.
  • *ptime — process time since the latest call.
  • *ref — incremental reference clock cycles since the latest call.
  • *core — incremental core clock cycles since the latest call.
  • *evt — events since the latest call.
  • *epc — incremental events per cycle since the latest 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 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. Setup era, honestly. ✨

Subsequent calls will read the counters and return real time, process time, event counts, the core and reference cycle count and EPC rate since the latest call to PAPI_epc(). Numbers go brrr. 📊

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. Note that PAPI_epc() is thread-safe and can therefore be called by multiple threads. Multi-thread bestie approved. 🫶

🦋 See also 🦋

  • PAPI_flips_rate()
  • PAPI_flops_rate()
  • PAPI_ipc()
  • PAPI_rate_stop()

⭐ Author ⭐

Literally generated automatically by Doxygen for PAPI from the source code.

Okay that's the whole page. Sign-off tea: version 7.2.0.0, dated Wed Jun 25 2025 19:30:48, and it's the PAPI_epc(3) page. Stay iconic, bestie. 💖✨

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