// Copyright 2019 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include <fcntl.h>
#include <fuchsia/hardware/goldfish/pipe/c/fidl.h>
#include <lib/fdio/fdio.h>
#include <lib/zx/channel.h>
#include <lib/zx/time.h>
#include <lib/zx/vmo.h>
#include <stdio.h>
#include <unistd.h>
#include <zircon/assert.h>
#include <zircon/syscalls.h>

#include <memory>

namespace {

// Lines of text for each result are prefixed with this.
constexpr const char* kTestOutputPrefix = "  - ";

// The number of warm up iterations prior to test runs.
constexpr unsigned kWarmUpIterations = 5;

// The number of test runs to do.
constexpr unsigned kNumTestRuns = 10;

// Kilobyte.
constexpr unsigned kKb = 1024;

// Megabyte.
constexpr unsigned kMb = kKb * kKb;

unsigned SizeValue(unsigned size) {
    if (size >= kMb) {
        return size / kMb;
    }
    if (size >= kKb) {
        return size / kKb;
    }
    return size;
}

const char* SizeSuffix(unsigned size) {
    if (size >= kMb) {
        return "MiB";
    }
    if (size >= kKb) {
        return "KiB";
    }
    return "B";
}

// Measures how long it takes to run some number of iterations of a closure.
// Returns a value in microseconds.
template <typename T> float Measure(unsigned iterations, const T& closure) {
    zx_ticks_t start = zx_ticks_get();
    for (unsigned i = 0; i < iterations; ++i) {
        closure();
    }
    zx_ticks_t stop = zx_ticks_get();
    return (static_cast<float>(stop - start) * 1000000.f /
            static_cast<float>(zx_ticks_per_second()));
}

// Runs a closure repeatedly and prints its timing.
template <typename T>
void RunAndMeasure(const char* test_name, unsigned iterations,
                   const T& closure) {
    printf("\n* %s ...\n", test_name);

    float warm_up_time = Measure(kWarmUpIterations, closure);

    printf("%swarm-up: %u iterations in %.3f us, %.3f us per iteration\n",
           kTestOutputPrefix, kWarmUpIterations, warm_up_time,
           warm_up_time / kWarmUpIterations);

    float run_times[kNumTestRuns];
    for (unsigned i = 0; i < kNumTestRuns; ++i) {
        run_times[i] = Measure(iterations, closure);
        zx::nanosleep(zx::deadline_after(zx::msec(10)));
    }

    float min = 0, max = 0;
    float cumulative = 0;
    for (const auto rt : run_times) {
        if (min == 0 || min > rt) {
            min = rt;
        }
        if (max == 0 || max < rt) {
            max = rt;
        }
        cumulative += rt;
    }
    float average = cumulative / kNumTestRuns;

    printf("%srun: %u test runs, %u iterations per run\n", kTestOutputPrefix,
           kNumTestRuns, iterations);
    printf("%stotal (usec): min: %.3f, max: %.3f, ave: %.3f\n",
           kTestOutputPrefix, min, max, average);
    printf("%sper-iteration (usec): min: %.3f\n",
           // The static cast is to avoid a "may change value" warning.
           kTestOutputPrefix, min / static_cast<float>(iterations));
}

void RunPingPongBenchmark(zx_handle_t channel, unsigned size,
                          unsigned iterations) {
    int32_t res;
    ZX_ASSERT(fuchsia_hardware_goldfish_pipe_DeviceSetBufferSize(
                  channel, size, &res) == ZX_OK);
    ZX_ASSERT(res == ZX_OK);

    zx::vmo vmo;
    ZX_ASSERT(fuchsia_hardware_goldfish_pipe_DeviceGetBuffer(
                  channel, &res, vmo.reset_and_get_address()) == ZX_OK);
    ZX_ASSERT(res == ZX_OK);

    {
        auto buffer = std::make_unique<uint8_t[]>(size);
        uint8_t* data = buffer.get();
        memset(data, 0xff, size);
        vmo.write(data, 0, size);
    }

    char test_name[64];
    snprintf(test_name, sizeof(test_name), "pingpong, %u%s", SizeValue(size),
             SizeSuffix(size));

    RunAndMeasure(test_name, iterations, [channel, size] {
        int32_t res;
        uint64_t actual;
        ZX_ASSERT(fuchsia_hardware_goldfish_pipe_DeviceWrite(
                      channel, size, 0, &res, &actual) == ZX_OK);
        ZX_ASSERT(res == ZX_OK);
        ZX_ASSERT(actual == size);
        ZX_ASSERT(fuchsia_hardware_goldfish_pipe_DeviceRead(
                      channel, size, 0, &res, &actual) == ZX_OK);
        ZX_ASSERT(res == ZX_OK);
        ZX_ASSERT(actual == size);
    });
}

} // namespace

int main(int argc, char** argv) {
    int fd = open("/dev/class/goldfish-pipe/000", O_RDWR);
    ZX_ASSERT(fd >= 0);

    zx::channel channel;
    ZX_ASSERT(fdio_get_service_handle(fd, channel.reset_and_get_address()) ==
              ZX_OK);

    int32_t res;
    zx::vmo vmo;
    ZX_ASSERT(fuchsia_hardware_goldfish_pipe_DeviceGetBuffer(
                  channel.get(), &res, vmo.reset_and_get_address()) == ZX_OK);
    ZX_ASSERT(res == ZX_OK);

    // Connect to pingpong service.
    constexpr char kPipeName[] = "pipe:pingpong";
    size_t bytes = strlen(kPipeName) + 1;
    ZX_ASSERT(vmo.write(kPipeName, 0, bytes) == ZX_OK);
    uint64_t actual;
    ZX_ASSERT(fuchsia_hardware_goldfish_pipe_DeviceWrite(
                  channel.get(), bytes, 0, &res, &actual) == ZX_OK);
    ZX_ASSERT(res == ZX_OK);
    ZX_ASSERT(actual == bytes);

    RunPingPongBenchmark(channel.get(), kMb, 50);
    RunPingPongBenchmark(channel.get(), ZX_PAGE_SIZE, kKb);

    printf("\nGoldfish benchmarks completed.\n");

    return 0;
}