🧮 perf_count.h

Easily setup and read perf counters on just a portion of code. Only works on Linux (since perf is a Linux feature). Supported on any version of C, ANSI and onward.

Usage

Just include perf_count.h header file in your C/C++ program.

Basic usage looks like:

#include <stdio.h>
#include "perf_count.h"

int main() {
    struct perf_counter cycles;
    perf_counter_setup(&cycles, PERF_TYPE_HARDWARE, PERF_COUNT_HW_CPU_CYCLES);
    perf_counter_start(&cycles);

    // code to profile...

    perf_counter_stop(&cycles);

    int64_t num_cycles = perf_counter_read(&cycles);
    printf("took %zd cycles to run.\n", num_cycles);
}

gcc your_c_file.c
sudo ./a.out

We require sudo to setup the hardware perf counter.

See a full example in the examples dir.

Full API

int perf_counter_setup(struct perf_counter *pc, uint32_t type, uint64_t config)

Setup perf_counter struct to listen to event specified by type and config. Returns 0 if successful, returns -1 on error.

See all possible types and configs here (under "config" field).

void perf_counter_start(struct perf_counter *pc)

Starts perf counter.

void perf_counter_stop(struct perf_counter *pc)

Stops perf counter.

uint64_t perf_counter_get_count(struct perf_counter *pc)

Returns value of specified perf counter.

FAQ

(ISO C99 and later) Why am I getting `warning: implicit declaration of function ‘syscall’ [-Wimplicit-function-declaration]`?

This might be because you are #include-ing a header file before _GNU_SOURCE is defined. Either add #define _GNU_SOURCE before you include any headers or move #include "perf_count.h" to the top of your imports.