//
// Copyright (c) 2015 Advanced Micro Devices, Inc. All rights reserved.
//
#include "platform/command.hpp"
#include "device/devkernel.hpp"
#include "device/devwavelimiter.hpp"
#include "os/os.hpp"
#include "utils/flags.hpp"

#include <cstdlib>
using namespace std;

namespace device {

uint WaveLimiter::MaxWave;
uint WaveLimiter::RunCount;
uint WaveLimiter::AdaptCount;

// ================================================================================================
WaveLimiter::WaveLimiter(WaveLimiterManager* manager, uint seqNum, bool enable, bool enableDump)
    : manager_(manager), dumper_(manager_->name() + "_" + std::to_string(seqNum), enableDump) {
  setIfNotDefault(SIMDPerSH_, GPU_WAVE_LIMIT_CU_PER_SH, manager->getSimdPerSH());
  MaxWave = GPU_WAVE_LIMIT_MAX_WAVE;
  RunCount = GPU_WAVE_LIMIT_RUN * MaxWave;
  AdaptCount = MaxContinuousSamples * 2 * (MaxWave + 1);

  state_ = WARMUP;
  if (!flagIsDefault(GPU_WAVE_LIMIT_TRACE)) {
    traceStream_.open(std::string(GPU_WAVE_LIMIT_TRACE) + manager_->name() + ".txt");
  }

  waves_ = MaxWave;
  enable_ = (SIMDPerSH_ == 0) ? false : enable;
  bestWave_ = (enable_) ? MaxWave : 0;
  worstWave_ = 0;
  sampleCount_ = 0;
  resultCount_ = 0;
  numContinuousSamples_ = 0;
}

// ================================================================================================
WaveLimiter::~WaveLimiter() {
  if (traceStream_.is_open()) {
    traceStream_.close();
  }
}

// ================================================================================================
uint WaveLimiter::getWavesPerSH() {
  // Generate different wave counts in the adaptation mode
  if ((state_ == ADAPT) && (sampleCount_ < AdaptCount)) {
    if (numContinuousSamples_ == 0) {
        ++waves_;
        waves_ %= MaxWave + 1;
        // Don't execute the wave count with the worst performance
        if (waves_ != 0) {
          while (worstWave_ >= waves_) {
            ++waves_;
            waves_ %= MaxWave + 1;
          }
        }
    }
    ++numContinuousSamples_;
    numContinuousSamples_ %= MaxContinuousSamples;
    ++sampleCount_;
  }
  else {
    waves_ = bestWave_;
  }
  return waves_ * SIMDPerSH_;
}

// ================================================================================================
WLAlgorithmSmooth::WLAlgorithmSmooth(WaveLimiterManager* manager, uint seqNum, bool enable,
                                     bool enableDump)
    : WaveLimiter(manager, seqNum, enable, enableDump) {
  dynRunCount_ = RunCount;
  adpMeasure_.resize(MaxWave + 1);
  adpSampleCnt_.resize(MaxWave + 1);
  runMeasure_.resize(MaxWave + 1);
  runSampleCnt_.resize(MaxWave + 1);

  clearData();
}

// ================================================================================================
WLAlgorithmSmooth::~WLAlgorithmSmooth() {}

// ================================================================================================
void WLAlgorithmSmooth::clearData() {
  waves_ = MaxWave;
  countAll_ = 0;
  clear(adpMeasure_);
  clear(adpSampleCnt_);
  dataCount_ = 0;
}

// ================================================================================================
void WLAlgorithmSmooth::updateData(ulong time) {
}

// ================================================================================================
void WLAlgorithmSmooth::outputTrace() {
  if (!traceStream_.is_open()) {
    return;
  }

  traceStream_ << "[WaveLimiter] " << manager_->name() << " state=" << state_ <<
    " waves=" << waves_ << " bestWave=" << bestWave_ << " worstWave=" << worstWave_ << '\n';
  output(traceStream_, "\n adaptive measure = ", adpMeasure_);
  output(traceStream_, "\n adaptive smaple count = ", adpSampleCnt_);
  output(traceStream_, "\n run measure = ", runMeasure_);
  output(traceStream_, "\n run smaple count = ", runSampleCnt_);
  traceStream_ << "\n % time from the previous runs to the best wave: ";
  float min = static_cast<float>(adpMeasure_[bestWave_]) / adpSampleCnt_[bestWave_];
  for (uint i = 0; i < (MaxWave + 1); ++i) {
    runSampleCnt_[i] = (runSampleCnt_[i] == 0) ? 1 : runSampleCnt_[i];
    float average = static_cast<float>(runMeasure_[i]) / runSampleCnt_[i];
    traceStream_ << (average * 100 / min) << " ";
  }
  traceStream_ << "\n run count = " << dynRunCount_;
  traceStream_ << "\n\n";
}

// ================================================================================================
void WLAlgorithmSmooth::callback(ulong duration, uint32_t waves) {
  dumper_.addData(duration, waves, static_cast<char>(state_));

  if (!enable_ || (duration == 0)) {
    return;
  }

  countAll_++;

  waves /= SIMDPerSH_;
  // Collect the time for the current wave count
  runMeasure_[waves] += duration;
  runSampleCnt_[waves]++;

  switch (state_) {
    case ADAPT:
      assert(duration > 0);
      // Wave count 0 indicates the satrt of adaptation
      if ((waves == 0) || (resultCount_ > 0)) {
        // Scale time to us
        adpMeasure_[waves] += duration;
        adpSampleCnt_[waves]++;
        resultCount_++;
        // If the end of adaptation is reached, then analyze the results
        if (resultCount_ == AdaptCount) {
          // Reset the counters
          resultCount_ = sampleCount_ = 0;
          float min = std::numeric_limits<float>::max();
          float max = std::numeric_limits<float>::min();
          uint32_t best = bestWave_;
          // Check performance for the previous run if it's available
          if (runSampleCnt_[bestWave_] > 0) {
            min = static_cast<float>(runMeasure_[bestWave_]) / runSampleCnt_[bestWave_];
          }
          else if (adpSampleCnt_[MaxWave] > 0) {
            min = static_cast<float>(adpMeasure_[MaxWave]) / adpSampleCnt_[MaxWave];
            bestWave_ = MaxWave;
          }
          // Find the fastest average time
          float reference = min;
          for (uint i = MaxWave; i > 0; --i) {
            float average;
            if (adpSampleCnt_[i] > 0) {
              average = static_cast<float>(adpMeasure_[i]) / adpSampleCnt_[i];
            }
            else {
              average = 0.0f;
            }
            // More waves have 5% advantage over the lower number
            if (average * 1.05f < min) {
              min = average;
              bestWave_ = i;
            }
            if (average > max) {
              max = average;
              worstWave_ = i;
            }
          }
          // Check for 5% acceptance
          if ((min * 1.05f > reference) || (bestWave_ == best)) {
            bestWave_ = best;
            // Increase the run time if the same wave count is the best
            dynRunCount_ += RunCount;
            dynRunCount_++;
          }
          else {
            dynRunCount_ = RunCount;
          }
          // Find the middle between the best and the worst
          if (worstWave_ < bestWave_) {
            worstWave_ += ((bestWave_ - worstWave_) >> 1);
          } else {
            worstWave_ = 0;
          }
          state_ = RUN;
          outputTrace();
          // Start to collect the new data for the best wave
          countAll_ = 0;
          runMeasure_[bestWave_] = 0;
          runSampleCnt_[bestWave_] = 0;
        }
      }
      return;
    case WARMUP:
    case RUN:
      if (countAll_ < dynRunCount_) {
        return;
      }
      if (state_ == WARMUP) {
        runSampleCnt_[bestWave_] = 0;
      }
      state_ = ADAPT;
      clearData();
      return;
  }
}

// ================================================================================================
WaveLimiter::DataDumper::DataDumper(const std::string& kernelName, bool enable) {
  enable_ = enable;
  if (enable_) {
    fileName_ = std::string(GPU_WAVE_LIMIT_DUMP) + kernelName + ".csv";
  }
}

// ================================================================================================
WaveLimiter::DataDumper::~DataDumper() {
  if (!enable_) {
    return;
  }

  std::ofstream OFS(fileName_);
  for (size_t i = 0, e = time_.size(); i != e; ++i) {
    OFS << i << ',' << time_[i] << ',' << wavePerSIMD_[i] << ',' << static_cast<uint>(state_[i])
        << '\n';
  }
  OFS.close();
}

// ================================================================================================
void WaveLimiter::DataDumper::addData(ulong time, uint wave, char state) {
  if (!enable_) {
    return;
  }

  time_.push_back(time);
  wavePerSIMD_.push_back(wave);
  state_.push_back(state);
}

// ================================================================================================
WaveLimiterManager::WaveLimiterManager(device::Kernel* kernel, const uint simdPerSH)
    : owner_(kernel), enable_(false), enableDump_(!flagIsDefault(GPU_WAVE_LIMIT_DUMP)) {
  setIfNotDefault(simdPerSH_, GPU_WAVE_LIMIT_CU_PER_SH, ((simdPerSH == 0) ? 1 : simdPerSH));
  fixed_ = GPU_WAVES_PER_SIMD * simdPerSH_;
}

// ================================================================================================
WaveLimiterManager::~WaveLimiterManager() {
  for (auto& I : limiters_) {
    delete I.second;
  }
}

// ================================================================================================
const std::string& WaveLimiterManager::name() const { return owner_->name(); }

// ================================================================================================
uint WaveLimiterManager::getWavesPerSH(const device::VirtualDevice* vdev) const {
  if (fixed_ > 0) {
    return fixed_;
  }
  if (!enable_) {
    return 0;
  }
  auto loc = limiters_.find(vdev);
  if (loc == limiters_.end()) {
    return 0;
  }
  assert(loc->second != nullptr);
  return loc->second->getWavesPerSH();
}

amd::ProfilingCallback* WaveLimiterManager::getProfilingCallback(
    const device::VirtualDevice* vdev) {
  assert(vdev != nullptr);
  if (!enable_ && !enableDump_) {
    return nullptr;
  }

  amd::ScopedLock SL(monitor_);
  auto loc = limiters_.find(vdev);
  if (loc != limiters_.end()) {
    return loc->second;
  }

  auto limiter = new WLAlgorithmSmooth(this, limiters_.size(), enable_, enableDump_);
  if (limiter == nullptr) {
    enable_ = false;
    return nullptr;
  }
  limiters_[vdev] = limiter;
  return limiter;
}

// ================================================================================================
void WaveLimiterManager::enable(bool isSupported) {
  if (fixed_ > 0) {
    return;
  }

  // Enable it only for CI+, unless GPU_WAVE_LIMIT_ENABLE is set to 1
  // Disabled for SI due to bug #10817
  if (!flagIsDefault(GPU_WAVE_LIMIT_ENABLE)) {
    enable_ = GPU_WAVE_LIMIT_ENABLE;
  } else if (isSupported) {
    if (owner_->workGroupInfo()->wavesPerSimdHint_ == 0) {
      enable_ = true;
    } else if (owner_->workGroupInfo()->wavesPerSimdHint_ <= GPU_WAVE_LIMIT_MAX_WAVE) {
      fixed_ = owner_->workGroupInfo()->wavesPerSimdHint_ * getSimdPerSH();
    }
  }
}

}  // namespace pal