A tiny c++ profiler

profile.h

#include <assert.h>
#include <stdio.h>
#include <string.h>
#include <stdint.h>
#include <chrono>
static int64_t perf_counter_ns()
{
    using namespace std::chrono;
    return (int64_t) duration_cast<nanoseconds>(system_clock::now().time_since_epoch()).count();
}

static double clock_s()
{
    static int64_t init_time = perf_counter_ns();
    int64_t now = perf_counter_ns();
    double clock = (double) (now - init_time) * 1e-9;
    return clock;
}

struct Profile_Point {
    int64_t counter_sum_ns;
    int64_t runs;
    bool is_in_progress;

    Profile_Point* next;
    const char* name;
    const char* file;
    const char* function;
    int line;
};

struct Profiles {
    Profile_Point* profiles;
    int64_t count;
};

//Staic variables inside static inline functions in c++
// are guaranteed to be truly global (ie shared across translation units)
static inline Profiles* profiles_get()
{
    static Profiles profiles = {0};
    return &profiles;
}
 
static void profiles_print()
{
    typedef long long lli;
    printf("(%-3i)     avg         total       runs     location & name\n", (int) profiles_get()->count);
    for(Profile_Point* point = profiles_get()->profiles; point != NULL; point = point->next) {
        assert(point);
        double ns_to_ms = 1e-3;
        double avg_time = (double) point->counter_sum_ns / point->runs *ns_to_ms;
        double total_time = point->counter_sum_ns*ns_to_ms;

        printf("%13.4lf %13.2lf %10lli %s:%i ", avg_time, total_time, (lli) point->runs, point->function, point->line);
        if(point->name && strlen(point->name) > 0)
            printf("\"%s\"", point->name);
        printf("\n");
    }
}

static void profiles_print_once_every(double seconds)
{
    double now = clock_s();
    static double last_time = 0;
    if(last_time + seconds < now)
    {
        printf("\n\n");
        last_time = now;
        profiles_print();
    }
}

struct Profile_Running 
{
    int64_t start = 0;
    Profile_Point* point = NULL;

    Profile_Running(Profile_Point* point, const char* name, const char* file, const char* function, int line) {
        if(point->line == 0)
        {
            point->name = name;
            point->file = file;
            point->function = function;
            point->line = line;
            point->runs = 0;
            point->counter_sum_ns = 0;
            point->next = profiles_get()->profiles;
            profiles_get()->profiles = point;
            profiles_get()->count += 1;
        }

        this->point = point;
        start = perf_counter_ns();
        point->is_in_progress = true;
    }
    
    ~Profile_Running() {
        if(point->is_in_progress)
        {
            point->is_in_progress = false;
            int64_t end = perf_counter_ns();
            point->counter_sum_ns += end - start;
            point->runs += 1;
        }
    }
};

#define CONCAT_(a, b) a ## b
#define CONCAT(a, b) CONCAT_(a, b)
#define UNIQUE_NAME(name) CONCAT(name, __LINE__)

#ifndef _MSC_VER
    #define __FUNCTION__ __func__
#endif

//use this macro: PROFILE() or PROFILE("")
#define PROFILE(...) \
    static Profile_Point UNIQUE_NAME(__profile__) = {0}; \
    Profile_Running UNIQUE_NAME(__running__)(&UNIQUE_NAME(__profile__), "" __VA_ARGS__, __FILE__, __FUNCTION__, __LINE__) \
   

void profile_example()
{
    PROFILE(); //profiles this scope (entire function)

    {
        PROFILE("my_profile"); //profiles this scope and name it my_profile

        //do some work...
    }

    profiles_print(); //print the profiles
    // ... or print them with interval of at least 3 seconds
    profiles_print_once_every(3);
}