/*
 *
 * Copyright 2017 gRPC authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

/* Test various closure related operations */

#include <benchmark/benchmark.h>
#include <grpc/grpc.h>
#include <sstream>

#include "src/core/lib/gpr/spinlock.h"
#include "src/core/lib/iomgr/closure.h"
#include "src/core/lib/iomgr/combiner.h"
#include "src/core/lib/iomgr/exec_ctx.h"

#include "test/cpp/microbenchmarks/helpers.h"
#include "test/cpp/util/test_config.h"

auto& force_library_initialization = Library::get();

static void BM_NoOpExecCtx(benchmark::State& state) {
  TrackCounters track_counters;
  while (state.KeepRunning()) {
    grpc_core::ExecCtx exec_ctx;
  }
  track_counters.Finish(state);
}
BENCHMARK(BM_NoOpExecCtx);

static void BM_WellFlushed(benchmark::State& state) {
  TrackCounters track_counters;
  grpc_core::ExecCtx exec_ctx;
  while (state.KeepRunning()) {
    grpc_core::ExecCtx::Get()->Flush();
  }

  track_counters.Finish(state);
}
BENCHMARK(BM_WellFlushed);

static void DoNothing(void* arg, grpc_error* error) {}

static void BM_ClosureInitAgainstExecCtx(benchmark::State& state) {
  TrackCounters track_counters;
  grpc_closure c;
  while (state.KeepRunning()) {
    benchmark::DoNotOptimize(
        GRPC_CLOSURE_INIT(&c, DoNothing, nullptr, grpc_schedule_on_exec_ctx));
  }
  track_counters.Finish(state);
}
BENCHMARK(BM_ClosureInitAgainstExecCtx);

static void BM_ClosureInitAgainstCombiner(benchmark::State& state) {
  TrackCounters track_counters;
  grpc_combiner* combiner = grpc_combiner_create();
  grpc_closure c;
  grpc_core::ExecCtx exec_ctx;
  while (state.KeepRunning()) {
    benchmark::DoNotOptimize(GRPC_CLOSURE_INIT(
        &c, DoNothing, nullptr, grpc_combiner_scheduler(combiner)));
  }
  GRPC_COMBINER_UNREF(combiner, "finished");

  track_counters.Finish(state);
}
BENCHMARK(BM_ClosureInitAgainstCombiner);

static void BM_ClosureRunOnExecCtx(benchmark::State& state) {
  TrackCounters track_counters;
  grpc_closure c;
  GRPC_CLOSURE_INIT(&c, DoNothing, nullptr, grpc_schedule_on_exec_ctx);
  grpc_core::ExecCtx exec_ctx;
  while (state.KeepRunning()) {
    GRPC_CLOSURE_RUN(&c, GRPC_ERROR_NONE);
    grpc_core::ExecCtx::Get()->Flush();
  }

  track_counters.Finish(state);
}
BENCHMARK(BM_ClosureRunOnExecCtx);

static void BM_ClosureCreateAndRun(benchmark::State& state) {
  TrackCounters track_counters;
  grpc_core::ExecCtx exec_ctx;
  while (state.KeepRunning()) {
    GRPC_CLOSURE_RUN(
        GRPC_CLOSURE_CREATE(DoNothing, nullptr, grpc_schedule_on_exec_ctx),
        GRPC_ERROR_NONE);
  }

  track_counters.Finish(state);
}
BENCHMARK(BM_ClosureCreateAndRun);

static void BM_ClosureInitAndRun(benchmark::State& state) {
  TrackCounters track_counters;
  grpc_core::ExecCtx exec_ctx;
  grpc_closure c;
  while (state.KeepRunning()) {
    GRPC_CLOSURE_RUN(
        GRPC_CLOSURE_INIT(&c, DoNothing, nullptr, grpc_schedule_on_exec_ctx),
        GRPC_ERROR_NONE);
  }

  track_counters.Finish(state);
}
BENCHMARK(BM_ClosureInitAndRun);

static void BM_ClosureSchedOnExecCtx(benchmark::State& state) {
  TrackCounters track_counters;
  grpc_closure c;
  GRPC_CLOSURE_INIT(&c, DoNothing, nullptr, grpc_schedule_on_exec_ctx);
  grpc_core::ExecCtx exec_ctx;
  while (state.KeepRunning()) {
    GRPC_CLOSURE_SCHED(&c, GRPC_ERROR_NONE);
    grpc_core::ExecCtx::Get()->Flush();
  }

  track_counters.Finish(state);
}
BENCHMARK(BM_ClosureSchedOnExecCtx);

static void BM_ClosureSched2OnExecCtx(benchmark::State& state) {
  TrackCounters track_counters;
  grpc_closure c1;
  grpc_closure c2;
  GRPC_CLOSURE_INIT(&c1, DoNothing, nullptr, grpc_schedule_on_exec_ctx);
  GRPC_CLOSURE_INIT(&c2, DoNothing, nullptr, grpc_schedule_on_exec_ctx);
  grpc_core::ExecCtx exec_ctx;
  while (state.KeepRunning()) {
    GRPC_CLOSURE_SCHED(&c1, GRPC_ERROR_NONE);
    GRPC_CLOSURE_SCHED(&c2, GRPC_ERROR_NONE);
    grpc_core::ExecCtx::Get()->Flush();
  }

  track_counters.Finish(state);
}
BENCHMARK(BM_ClosureSched2OnExecCtx);

static void BM_ClosureSched3OnExecCtx(benchmark::State& state) {
  TrackCounters track_counters;
  grpc_closure c1;
  grpc_closure c2;
  grpc_closure c3;
  GRPC_CLOSURE_INIT(&c1, DoNothing, nullptr, grpc_schedule_on_exec_ctx);
  GRPC_CLOSURE_INIT(&c2, DoNothing, nullptr, grpc_schedule_on_exec_ctx);
  GRPC_CLOSURE_INIT(&c3, DoNothing, nullptr, grpc_schedule_on_exec_ctx);
  grpc_core::ExecCtx exec_ctx;
  while (state.KeepRunning()) {
    GRPC_CLOSURE_SCHED(&c1, GRPC_ERROR_NONE);
    GRPC_CLOSURE_SCHED(&c2, GRPC_ERROR_NONE);
    GRPC_CLOSURE_SCHED(&c3, GRPC_ERROR_NONE);
    grpc_core::ExecCtx::Get()->Flush();
  }

  track_counters.Finish(state);
}
BENCHMARK(BM_ClosureSched3OnExecCtx);

static void BM_AcquireMutex(benchmark::State& state) {
  TrackCounters track_counters;
  // for comparison with the combiner stuff below
  gpr_mu mu;
  gpr_mu_init(&mu);
  grpc_core::ExecCtx exec_ctx;
  while (state.KeepRunning()) {
    gpr_mu_lock(&mu);
    DoNothing(nullptr, GRPC_ERROR_NONE);
    gpr_mu_unlock(&mu);
  }

  track_counters.Finish(state);
}
BENCHMARK(BM_AcquireMutex);

static void BM_TryAcquireMutex(benchmark::State& state) {
  TrackCounters track_counters;
  // for comparison with the combiner stuff below
  gpr_mu mu;
  gpr_mu_init(&mu);
  grpc_core::ExecCtx exec_ctx;
  while (state.KeepRunning()) {
    if (gpr_mu_trylock(&mu)) {
      DoNothing(nullptr, GRPC_ERROR_NONE);
      gpr_mu_unlock(&mu);
    } else {
      abort();
    }
  }

  track_counters.Finish(state);
}
BENCHMARK(BM_TryAcquireMutex);

static void BM_AcquireSpinlock(benchmark::State& state) {
  TrackCounters track_counters;
  // for comparison with the combiner stuff below
  gpr_spinlock mu = GPR_SPINLOCK_INITIALIZER;
  grpc_core::ExecCtx exec_ctx;
  while (state.KeepRunning()) {
    gpr_spinlock_lock(&mu);
    DoNothing(nullptr, GRPC_ERROR_NONE);
    gpr_spinlock_unlock(&mu);
  }

  track_counters.Finish(state);
}
BENCHMARK(BM_AcquireSpinlock);

static void BM_TryAcquireSpinlock(benchmark::State& state) {
  TrackCounters track_counters;
  // for comparison with the combiner stuff below
  gpr_spinlock mu = GPR_SPINLOCK_INITIALIZER;
  grpc_core::ExecCtx exec_ctx;
  while (state.KeepRunning()) {
    if (gpr_spinlock_trylock(&mu)) {
      DoNothing(nullptr, GRPC_ERROR_NONE);
      gpr_spinlock_unlock(&mu);
    } else {
      abort();
    }
  }

  track_counters.Finish(state);
}
BENCHMARK(BM_TryAcquireSpinlock);

static void BM_ClosureSchedOnCombiner(benchmark::State& state) {
  TrackCounters track_counters;
  grpc_combiner* combiner = grpc_combiner_create();
  grpc_closure c;
  GRPC_CLOSURE_INIT(&c, DoNothing, nullptr, grpc_combiner_scheduler(combiner));
  grpc_core::ExecCtx exec_ctx;
  while (state.KeepRunning()) {
    GRPC_CLOSURE_SCHED(&c, GRPC_ERROR_NONE);
    grpc_core::ExecCtx::Get()->Flush();
  }
  GRPC_COMBINER_UNREF(combiner, "finished");

  track_counters.Finish(state);
}
BENCHMARK(BM_ClosureSchedOnCombiner);

static void BM_ClosureSched2OnCombiner(benchmark::State& state) {
  TrackCounters track_counters;
  grpc_combiner* combiner = grpc_combiner_create();
  grpc_closure c1;
  grpc_closure c2;
  GRPC_CLOSURE_INIT(&c1, DoNothing, nullptr, grpc_combiner_scheduler(combiner));
  GRPC_CLOSURE_INIT(&c2, DoNothing, nullptr, grpc_combiner_scheduler(combiner));
  grpc_core::ExecCtx exec_ctx;
  while (state.KeepRunning()) {
    GRPC_CLOSURE_SCHED(&c1, GRPC_ERROR_NONE);
    GRPC_CLOSURE_SCHED(&c2, GRPC_ERROR_NONE);
    grpc_core::ExecCtx::Get()->Flush();
  }
  GRPC_COMBINER_UNREF(combiner, "finished");

  track_counters.Finish(state);
}
BENCHMARK(BM_ClosureSched2OnCombiner);

static void BM_ClosureSched3OnCombiner(benchmark::State& state) {
  TrackCounters track_counters;
  grpc_combiner* combiner = grpc_combiner_create();
  grpc_closure c1;
  grpc_closure c2;
  grpc_closure c3;
  GRPC_CLOSURE_INIT(&c1, DoNothing, nullptr, grpc_combiner_scheduler(combiner));
  GRPC_CLOSURE_INIT(&c2, DoNothing, nullptr, grpc_combiner_scheduler(combiner));
  GRPC_CLOSURE_INIT(&c3, DoNothing, nullptr, grpc_combiner_scheduler(combiner));
  grpc_core::ExecCtx exec_ctx;
  while (state.KeepRunning()) {
    GRPC_CLOSURE_SCHED(&c1, GRPC_ERROR_NONE);
    GRPC_CLOSURE_SCHED(&c2, GRPC_ERROR_NONE);
    GRPC_CLOSURE_SCHED(&c3, GRPC_ERROR_NONE);
    grpc_core::ExecCtx::Get()->Flush();
  }
  GRPC_COMBINER_UNREF(combiner, "finished");

  track_counters.Finish(state);
}
BENCHMARK(BM_ClosureSched3OnCombiner);

static void BM_ClosureSched2OnTwoCombiners(benchmark::State& state) {
  TrackCounters track_counters;
  grpc_combiner* combiner1 = grpc_combiner_create();
  grpc_combiner* combiner2 = grpc_combiner_create();
  grpc_closure c1;
  grpc_closure c2;
  GRPC_CLOSURE_INIT(&c1, DoNothing, nullptr,
                    grpc_combiner_scheduler(combiner1));
  GRPC_CLOSURE_INIT(&c2, DoNothing, nullptr,
                    grpc_combiner_scheduler(combiner2));
  grpc_core::ExecCtx exec_ctx;
  while (state.KeepRunning()) {
    GRPC_CLOSURE_SCHED(&c1, GRPC_ERROR_NONE);
    GRPC_CLOSURE_SCHED(&c2, GRPC_ERROR_NONE);
    grpc_core::ExecCtx::Get()->Flush();
  }
  GRPC_COMBINER_UNREF(combiner1, "finished");
  GRPC_COMBINER_UNREF(combiner2, "finished");

  track_counters.Finish(state);
}
BENCHMARK(BM_ClosureSched2OnTwoCombiners);

static void BM_ClosureSched4OnTwoCombiners(benchmark::State& state) {
  TrackCounters track_counters;
  grpc_combiner* combiner1 = grpc_combiner_create();
  grpc_combiner* combiner2 = grpc_combiner_create();
  grpc_closure c1;
  grpc_closure c2;
  grpc_closure c3;
  grpc_closure c4;
  GRPC_CLOSURE_INIT(&c1, DoNothing, nullptr,
                    grpc_combiner_scheduler(combiner1));
  GRPC_CLOSURE_INIT(&c2, DoNothing, nullptr,
                    grpc_combiner_scheduler(combiner2));
  GRPC_CLOSURE_INIT(&c3, DoNothing, nullptr,
                    grpc_combiner_scheduler(combiner1));
  GRPC_CLOSURE_INIT(&c4, DoNothing, nullptr,
                    grpc_combiner_scheduler(combiner2));
  grpc_core::ExecCtx exec_ctx;
  while (state.KeepRunning()) {
    GRPC_CLOSURE_SCHED(&c1, GRPC_ERROR_NONE);
    GRPC_CLOSURE_SCHED(&c2, GRPC_ERROR_NONE);
    GRPC_CLOSURE_SCHED(&c3, GRPC_ERROR_NONE);
    GRPC_CLOSURE_SCHED(&c4, GRPC_ERROR_NONE);
    grpc_core::ExecCtx::Get()->Flush();
  }
  GRPC_COMBINER_UNREF(combiner1, "finished");
  GRPC_COMBINER_UNREF(combiner2, "finished");

  track_counters.Finish(state);
}
BENCHMARK(BM_ClosureSched4OnTwoCombiners);

// Helper that continuously reschedules the same closure against something until
// the benchmark is complete
class Rescheduler {
 public:
  Rescheduler(benchmark::State& state, grpc_closure_scheduler* scheduler)
      : state_(state) {
    GRPC_CLOSURE_INIT(&closure_, Step, this, scheduler);
  }

  void ScheduleFirst() { GRPC_CLOSURE_SCHED(&closure_, GRPC_ERROR_NONE); }

  void ScheduleFirstAgainstDifferentScheduler(
      grpc_closure_scheduler* scheduler) {
    GRPC_CLOSURE_SCHED(GRPC_CLOSURE_CREATE(Step, this, scheduler),
                       GRPC_ERROR_NONE);
  }

 private:
  benchmark::State& state_;
  grpc_closure closure_;

  static void Step(void* arg, grpc_error* error) {
    Rescheduler* self = static_cast<Rescheduler*>(arg);
    if (self->state_.KeepRunning()) {
      GRPC_CLOSURE_SCHED(&self->closure_, GRPC_ERROR_NONE);
    }
  }
};

static void BM_ClosureReschedOnExecCtx(benchmark::State& state) {
  TrackCounters track_counters;
  grpc_core::ExecCtx exec_ctx;
  Rescheduler r(state, grpc_schedule_on_exec_ctx);
  r.ScheduleFirst();
  grpc_core::ExecCtx::Get()->Flush();
  track_counters.Finish(state);
}
BENCHMARK(BM_ClosureReschedOnExecCtx);

static void BM_ClosureReschedOnCombiner(benchmark::State& state) {
  TrackCounters track_counters;
  grpc_core::ExecCtx exec_ctx;
  grpc_combiner* combiner = grpc_combiner_create();
  Rescheduler r(state, grpc_combiner_scheduler(combiner));
  r.ScheduleFirst();
  grpc_core::ExecCtx::Get()->Flush();
  GRPC_COMBINER_UNREF(combiner, "finished");

  track_counters.Finish(state);
}
BENCHMARK(BM_ClosureReschedOnCombiner);

static void BM_ClosureReschedOnCombinerFinally(benchmark::State& state) {
  TrackCounters track_counters;
  grpc_core::ExecCtx exec_ctx;
  grpc_combiner* combiner = grpc_combiner_create();
  Rescheduler r(state, grpc_combiner_finally_scheduler(combiner));
  r.ScheduleFirstAgainstDifferentScheduler(grpc_combiner_scheduler(combiner));
  grpc_core::ExecCtx::Get()->Flush();
  GRPC_COMBINER_UNREF(combiner, "finished");

  track_counters.Finish(state);
}
BENCHMARK(BM_ClosureReschedOnCombinerFinally);

// Some distros have RunSpecifiedBenchmarks under the benchmark namespace,
// and others do not. This allows us to support both modes.
namespace benchmark {
void RunTheBenchmarksNamespaced() { RunSpecifiedBenchmarks(); }
}  // namespace benchmark

int main(int argc, char** argv) {
  ::benchmark::Initialize(&argc, argv);
  ::grpc::testing::InitTest(&argc, &argv, false);
  benchmark::RunTheBenchmarksNamespaced();
  return 0;
}