src/tests/benchmarks/fidl/llcpp/send_event_benchmark_util.h

// Copyright 2020 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.

#ifndef SRC_TESTS_BENCHMARKS_FIDL_LLCPP_SEND_EVENT_BENCHMARK_UTIL_H_
#define SRC_TESTS_BENCHMARKS_FIDL_LLCPP_SEND_EVENT_BENCHMARK_UTIL_H_

#include <lib/fidl/llcpp/coding.h>
#include <zircon/status.h>
#include <zircon/types.h>

#include <algorithm>
#include <thread>
#include <type_traits>

#include <perftest/perftest.h>

namespace llcpp_benchmarks {

template <typename ProtocolType, typename BuilderFunc>
bool SendEventBenchmark(perftest::RepeatState* state, BuilderFunc builder) {
  using FidlType = std::invoke_result_t<BuilderFunc>;
  static_assert(fidl::IsFidlType<FidlType>::value, "FIDL type required");

  state->DeclareStep("Setup/WallTime");
  state->DeclareStep("SendEvent/WallTime");
  state->DeclareStep("Teardown/WallTime");

  zx::channel sender_channel, receiver_channel;
  zx_status_t status = zx::channel::create(0, &sender_channel, &receiver_channel);
  ZX_ASSERT(status == ZX_OK);

  class EventHandler : public ProtocolType::SyncEventHandler {
   public:
    EventHandler(perftest::RepeatState* state, bool& ready, std::mutex& mu,
                 std::condition_variable& cond)
        : state_(state), ready_(ready), mu_(mu), cond_(cond) {}

    void Send(typename ProtocolType::SendResponse* event) override {
      state_->NextStep();  // End: SendEvent. Begin: Teardown.
      {
        std::lock_guard<std::mutex> guard(mu_);
        ready_ = true;
      }
      cond_.notify_one();
    }

    zx_status_t Unknown() override { return ZX_ERR_NOT_SUPPORTED; }

   private:
    perftest::RepeatState* state_;
    bool& ready_;
    std::mutex& mu_;
    std::condition_variable& cond_;
  };

  bool ready = false;
  std::mutex mu;
  std::condition_variable cond;

  std::thread receiver_thread([channel = std::move(receiver_channel), state, &ready, &mu, &cond]() {
    EventHandler event_handler(state, ready, mu, cond);
    while (event_handler.HandleOneEvent(channel.borrow()).ok()) {
    }
  });

  typename ProtocolType::EventSender sender(std::move(sender_channel));
  while (state->KeepRunning()) {
    fidl::aligned<FidlType> aligned_value = builder();

    state->NextStep();  // End: Setup. Begin: SendEvent.

    sender.Send(std::move(aligned_value.value));

    {
      std::unique_lock<std::mutex> lock(mu);
      while (!ready) {
        cond.wait(lock);
      }
      ready = false;
    }
  }

  // close the channel
  sender.channel().reset();
  receiver_thread.join();

  return true;
}

}  // namespace llcpp_benchmarks

#endif  // SRC_TESTS_BENCHMARKS_FIDL_LLCPP_SEND_EVENT_BENCHMARK_UTIL_H_