/*
Copyright (c) 2020 - 2021 Advanced Micro Devices, Inc. All rights reserved.
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
*/

#include <stdio.h>
#include "hip/hip_runtime.h"
#ifdef __HIP_PLATFORM_AMD__
#include "hip/hip_ext.h"
#endif
#include <iostream>
#include <fstream>
#include <chrono>
#include <algorithm>
#include <atomic>
#include <thread>
#include <future>
#include <functional>
#include <vector>

#define NUM_GROUPS 1
#define GROUP_SIZE 1
#define WARMUP_RUN_COUNT 10
#define TIMING_RUN_COUNT 100
#define TOTAL_RUN_COUNT WARMUP_RUN_COUNT + TIMING_RUN_COUNT
#define FILENAME "test_kernel.code"
#define failed(...)                                                                                \
    abort();

#define HIPCHECK(error)                                                                            \
    {                                                                                              \
        hipError_t localError = error;                                                             \
        if ((localError != hipSuccess) && (localError != hipErrorPeerAccessAlreadyEnabled)) {      \
            printf("error: '%s'(%d) from %s at %s:%d\n",  hipGetErrorString(localError),           \
                   localError, #error, __FILE__, __LINE__);                                        \
                   failed("API returned error code.");                                             \
        }                                                                                          \
    }


__global__ void EmptyKernel() {}

// Helper to print various timing metrics
void print_timing(std::string test, std::array<float, TOTAL_RUN_COUNT> &results, int batch = 1)
{

    float total_us = 0.0f, mean_us = 0.0f, stddev_us = 0.0f;

    // remove top outliers due to nature of variability across large number of multi-threaded runs
    std::sort(results.begin(), results.end(), std::greater<float>());
    auto start_iter = std::next(results.begin(), WARMUP_RUN_COUNT);
    auto end_iter = results.end();

    // mean
    std::for_each(start_iter, end_iter, [&](const float &run_ms) {
        total_us += (run_ms * 1000) / batch;
    });
    mean_us = total_us  / TIMING_RUN_COUNT;

   // stddev
    total_us = 0;
    std::for_each(start_iter, end_iter, [&](const float &run_ms) {
        float dev_us = ((run_ms * 1000) / batch) - mean_us;
        total_us += dev_us * dev_us;
    });
    stddev_us = sqrt(total_us / TIMING_RUN_COUNT);

    printf("\n %s: %.1f us, std: %.1f us\n", test.c_str(), mean_us, stddev_us);
}

// Measure time taken to enqueue a kernel on the GPU using hipModuleLaunchKernel
void hipModuleLaunchKernel_enqueue_rate(const std::vector<char>& buffer, std::atomic_int* shared, int max_threads)
{
    //resources necessary for this thread
    hipStream_t stream;
    HIPCHECK(hipStreamCreate(&stream));
    hipModule_t module;
    hipFunction_t function;

    HIPCHECK(hipModuleLoadData(&module, &buffer[0]));
    HIPCHECK(hipModuleGetFunction(&function, module, "test"));

    void* kernel_params = nullptr;
    std::array<float, TOTAL_RUN_COUNT> results;

    //synchronize all threads, before running
    int tid = shared->fetch_add(1, std::memory_order_release);
    while (max_threads != shared->load(std::memory_order_acquire)) {}

    for (auto i = 0; i < TOTAL_RUN_COUNT; ++i) {
        auto start = std::chrono::high_resolution_clock::now();
        HIPCHECK(hipModuleLaunchKernel(function, 1, 1, 1, 1, 1, 1, 0, stream, &kernel_params, nullptr));
        auto stop = std::chrono::high_resolution_clock::now();
        results[i] = std::chrono::duration<double, std::milli>(stop - start).count();
    }
    HIPCHECK(hipModuleUnload(module));
    print_timing("Thread ID : " + std::to_string(tid) + " , " + "hipModuleLaunchKernel enqueue rate", results);
    HIPCHECK(hipStreamDestroy(stream));
}

// Measure time taken to enqueue a kernel on the GPU using hipLaunchKernelGGL
void hipLaunchKernelGGL_enqueue_rate(const std::vector<char>& buffer, std::atomic_int* shared, int max_threads)
{
    //resources necessary for this thread
    hipStream_t stream;
    HIPCHECK(hipStreamCreate(&stream));
    std::array<float, TOTAL_RUN_COUNT> results;

    //synchronize all threads, before running
    int tid = shared->fetch_add(1, std::memory_order_release);
    while (max_threads != shared->load(std::memory_order_acquire)) {}

    for (auto i = 0; i < TOTAL_RUN_COUNT; ++i) {
        auto start = std::chrono::high_resolution_clock::now();
        hipLaunchKernelGGL((EmptyKernel), dim3(NUM_GROUPS), dim3(GROUP_SIZE), 0, stream);
        auto stop = std::chrono::high_resolution_clock::now();
        results[i] = std::chrono::duration<double, std::milli>(stop - start).count();
    }
    print_timing("Thread ID : " + std::to_string(tid) + " , " + "hipLaunchKernelGGL enqueue rate", results);
    HIPCHECK(hipStreamDestroy(stream));
}

// Simple thread pool
struct thread_pool {
    thread_pool(int total_threads) : max_threads(total_threads) {
        std::ifstream file(FILENAME, std::ios::binary | std::ios::ate);
        std::streamsize fsize = file.tellg();
        file.seekg(0, std::ios::beg);

        buffer.resize(fsize);
        if (!file.read(buffer.data(), fsize)) {
            failed("could not open code object '%s'\n", FILENAME);
        }
        file.close();
    }
    void start(std::function<void(const std::vector<char>&, std::atomic_int*, int)> f) {
        for (int i = 0; i < max_threads; ++i) {
            threads.push_back(std::async(std::launch::async, f, std::ref(buffer), &shared, max_threads));
        }
    }
    void finish() {
        for (auto&&thread : threads) {
            thread.get();
        }
        threads.clear();
        shared = 0;
    }
    ~thread_pool() {
        finish();
    }
private:
    std::atomic_int shared {0};
    std::vector<char> buffer;
    std::vector<std::future<void>> threads;
    int max_threads = 1;
};


int main(int argc, char* argv[])
{
    if (argc != 3) {
        std::cerr << "Run test as 'hipDispatchEnqueueRateMT <num_threads> <0-hipModuleLaunchKernel /1-hipLaunchKernelGGL>'\n";
        return -1;
    }
    int max_threads = atoi(argv[1]);
    int run_module_test = atoi(argv[2]);
    if(max_threads < 1 || run_module_test < 0 || run_module_test > 1) {
        std::cerr << "Invalid Input.\n";
        std::cerr << "Run test as 'hipDispatchEnqueueRateMT <num_threads> <0-hipModuleLaunchKernel /1-hipLaunchKernelGGL>'\n";
        return -1;
    }
    thread_pool task(max_threads);

    if(run_module_test == 0) {
        task.start(hipModuleLaunchKernel_enqueue_rate);
        task.finish();
    } else {
        task.start(hipLaunchKernelGGL_enqueue_rate);
        task.finish();
    }
    return 0;
}