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/* Benchmark gRPC end2end in various configurations */

#include <benchmark/benchmark.h>
#include "src/core/lib/profiling/timers.h"
#include "src/cpp/client/create_channel_internal.h"
#include "src/proto/grpc/testing/echo.grpc.pb.h"
#include "test/cpp/microbenchmarks/fullstack_context_mutators.h"
#include "test/cpp/microbenchmarks/fullstack_fixtures.h"
extern "C" {
#include "src/core/ext/transport/chttp2/transport/chttp2_transport.h"
#include "src/core/ext/transport/chttp2/transport/internal.h"
#include "test/core/util/trickle_endpoint.h"
}

namespace grpc {
namespace testing {

static void* tag(intptr_t x) { return reinterpret_cast<void*>(x); }

class TrickledCHTTP2 : public EndpointPairFixture {
 public:
  TrickledCHTTP2(Service* service, size_t megabits_per_second)
      : EndpointPairFixture(service, MakeEndpoints(megabits_per_second),
                            FixtureConfiguration()) {}

  void AddToLabel(std::ostream& out, benchmark::State& state) {
    out << " writes/iter:"
        << ((double)stats_.num_writes / (double)state.iterations())
        << " cli_transport_stalls/iter:"
        << ((double)
                client_stats_.streams_stalled_due_to_transport_flow_control /
            (double)state.iterations())
        << " cli_stream_stalls/iter:"
        << ((double)client_stats_.streams_stalled_due_to_stream_flow_control /
            (double)state.iterations())
        << " svr_transport_stalls/iter:"
        << ((double)
                server_stats_.streams_stalled_due_to_transport_flow_control /
            (double)state.iterations())
        << " svr_stream_stalls/iter:"
        << ((double)server_stats_.streams_stalled_due_to_stream_flow_control /
            (double)state.iterations());
  }

  void Step() {
    grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
    size_t client_backlog =
        grpc_trickle_endpoint_trickle(&exec_ctx, endpoint_pair_.client);
    size_t server_backlog =
        grpc_trickle_endpoint_trickle(&exec_ctx, endpoint_pair_.server);
    grpc_exec_ctx_finish(&exec_ctx);

    UpdateStats((grpc_chttp2_transport*)client_transport_, &client_stats_,
                client_backlog);
    UpdateStats((grpc_chttp2_transport*)server_transport_, &server_stats_,
                server_backlog);
  }

 private:
  grpc_passthru_endpoint_stats stats_;
  struct Stats {
    int streams_stalled_due_to_stream_flow_control = 0;
    int streams_stalled_due_to_transport_flow_control = 0;
  };
  Stats client_stats_;
  Stats server_stats_;

  grpc_endpoint_pair MakeEndpoints(size_t kilobits) {
    grpc_endpoint_pair p;
    grpc_passthru_endpoint_create(&p.client, &p.server, Library::get().rq(),
                                  &stats_);
    double bytes_per_second = 125.0 * kilobits;
    p.client = grpc_trickle_endpoint_create(p.client, bytes_per_second);
    p.server = grpc_trickle_endpoint_create(p.server, bytes_per_second);
    return p;
  }

  void UpdateStats(grpc_chttp2_transport* t, Stats* s, size_t backlog) {
    if (backlog == 0) {
      if (t->lists[GRPC_CHTTP2_LIST_STALLED_BY_STREAM].head != NULL) {
        s->streams_stalled_due_to_stream_flow_control++;
      }
      if (t->lists[GRPC_CHTTP2_LIST_STALLED_BY_TRANSPORT].head != NULL) {
        s->streams_stalled_due_to_transport_flow_control++;
      }
    }
  }
};

// force library initialization
auto& force_library_initialization = Library::get();

static void TrickleCQNext(TrickledCHTTP2* fixture, void** t, bool* ok) {
  while (true) {
    switch (fixture->cq()->AsyncNext(
        t, ok, gpr_time_add(gpr_now(GPR_CLOCK_MONOTONIC),
                            gpr_time_from_micros(100, GPR_TIMESPAN)))) {
      case CompletionQueue::TIMEOUT:
        fixture->Step();
        break;
      case CompletionQueue::SHUTDOWN:
        GPR_ASSERT(false);
        break;
      case CompletionQueue::GOT_EVENT:
        return;
    }
  }
}

static void BM_PumpStreamServerToClient_Trickle(benchmark::State& state) {
  EchoTestService::AsyncService service;
  std::unique_ptr<TrickledCHTTP2> fixture(
      new TrickledCHTTP2(&service, state.range(1)));
  {
    EchoResponse send_response;
    EchoResponse recv_response;
    if (state.range(0) > 0) {
      send_response.set_message(std::string(state.range(0), 'a'));
    }
    Status recv_status;
    ServerContext svr_ctx;
    ServerAsyncReaderWriter<EchoResponse, EchoRequest> response_rw(&svr_ctx);
    service.RequestBidiStream(&svr_ctx, &response_rw, fixture->cq(),
                              fixture->cq(), tag(0));
    std::unique_ptr<EchoTestService::Stub> stub(
        EchoTestService::NewStub(fixture->channel()));
    ClientContext cli_ctx;
    auto request_rw = stub->AsyncBidiStream(&cli_ctx, fixture->cq(), tag(1));
    int need_tags = (1 << 0) | (1 << 1);
    void* t;
    bool ok;
    while (need_tags) {
      TrickleCQNext(fixture.get(), &t, &ok);
      GPR_ASSERT(ok);
      int i = (int)(intptr_t)t;
      GPR_ASSERT(need_tags & (1 << i));
      need_tags &= ~(1 << i);
    }
    request_rw->Read(&recv_response, tag(0));
    while (state.KeepRunning()) {
      GPR_TIMER_SCOPE("BenchmarkCycle", 0);
      response_rw.Write(send_response, tag(1));
      while (true) {
        TrickleCQNext(fixture.get(), &t, &ok);
        if (t == tag(0)) {
          request_rw->Read(&recv_response, tag(0));
        } else if (t == tag(1)) {
          break;
        } else {
          GPR_ASSERT(false);
        }
      }
    }
    response_rw.Finish(Status::OK, tag(1));
    need_tags = (1 << 0) | (1 << 1);
    while (need_tags) {
      TrickleCQNext(fixture.get(), &t, &ok);
      int i = (int)(intptr_t)t;
      GPR_ASSERT(need_tags & (1 << i));
      need_tags &= ~(1 << i);
    }
  }
  fixture->Finish(state);
  fixture.reset();
  state.SetBytesProcessed(state.range(0) * state.iterations());
}

/*******************************************************************************
 * CONFIGURATIONS
 */

static void TrickleArgs(benchmark::internal::Benchmark* b) {
  for (int i = 1; i <= 128 * 1024 * 1024; i *= 8) {
    for (int j = 1; j <= 128 * 1024 * 1024; j *= 8) {
      double expected_time =
          static_cast<double>(14 + i) / (125.0 * static_cast<double>(j));
      if (expected_time > 0.01) continue;
      b->Args({i, j});
    }
  }
}

BENCHMARK(BM_PumpStreamServerToClient_Trickle)->Apply(TrickleArgs);
}
}

BENCHMARK_MAIN();