root/third_party/tcmalloc/vendor/src/tests/profile-handler_unittest.cc

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DEFINITIONS

This source file includes following definitions.
  1. SetJoinable
  2. Start
  3. Join
  4. DoRun
  5. Delay
  6. IsTimerEnabled
  7. Run
  8. threads_have_separate_timers
  9. stop_work
  10. set_stop_work
  11. Run
  12. Run
  13. TickCounter
  14. SetUpTestCase
  15. SetUp
  16. TearDown
  17. RegisterThread
  18. StartWorker
  19. StopWorker
  20. IsSignalEnabled
  21. GetCallbackCount
  22. GetInterruptCount
  23. VerifyRegistration
  24. VerifyUnregistration
  25. VerifyDisabled
  26. RegisterCallback
  27. UnregisterCallback
  28. RUN_ALL_TESTS
  29. TEST_F
  30. TEST_F
  31. TEST_F
  32. TEST_F
  33. main

// Copyright 2009 Google Inc. All Rights Reserved.
// Author: Nabeel Mian (nabeelmian@google.com)
//         Chris Demetriou (cgd@google.com)
//
// This file contains the unit tests for profile-handler.h interface.
//
// It is linked into three separate unit tests:
//     profile-handler_unittest tests basic functionality
//     profile-handler_disable_test tests that the profiler
//         is disabled with --install_signal_handlers=false
//     profile-handler_conflict_test tests that the profiler
//         is disabled when a SIGPROF handler is registered before InitGoogle.

#include "config.h"
#include "profile-handler.h"

#include <assert.h>
#include <pthread.h>
#include <sys/time.h>
#include <time.h>
#include "base/logging.h"
#include "base/simple_mutex.h"

// Some helpful macros for the test class
#define TEST_F(cls, fn)    void cls :: fn()

// Do we expect the profiler to be enabled?
DEFINE_bool(test_profiler_enabled, true,
            "expect profiler to be enabled during tests");

// Should we look at the kernel signal handler settings during the test?
// Not if we're in conflict_test, because we can't distinguish its nop
// handler from the real one.
DEFINE_bool(test_profiler_signal_handler, true,
            "check profiler signal handler during tests");

namespace {

// TODO(csilvers): error-checking on the pthreads routines
class Thread {
 public:
  Thread() : joinable_(false) { }
  void SetJoinable(bool value) { joinable_ = value; }
  void Start() {
    pthread_attr_t attr;
    pthread_attr_init(&attr);
    pthread_attr_setdetachstate(&attr, joinable_ ? PTHREAD_CREATE_JOINABLE
                                                 : PTHREAD_CREATE_DETACHED);
    pthread_create(&thread_, &attr, &DoRun, this);
    pthread_attr_destroy(&attr);
  }
  void Join()  {
    assert(joinable_);
    pthread_join(thread_, NULL);
  }
  virtual void Run() = 0;
 private:
  static void* DoRun(void* cls) {
    ProfileHandlerRegisterThread();
    reinterpret_cast<Thread*>(cls)->Run();
    return NULL;
  }
  pthread_t thread_;
  bool joinable_;
};

// Sleep interval in nano secs. ITIMER_PROF goes off only afer the specified CPU
// time is consumed. Under heavy load this process may no get scheduled in a
// timely fashion. Therefore, give enough time (20x of ProfileHandle timer
// interval 10ms (100Hz)) for this process to accumulate enought CPU time to get
// a profile tick.
int kSleepInterval = 200000000;

// Sleep interval in nano secs. To ensure that if the timer has expired it is
// reset.
int kTimerResetInterval = 5000000;

// Whether each thread has separate timers.
static bool timer_separate_ = false;
static int timer_type_ = ITIMER_PROF;
static int signal_number_ = SIGPROF;

// Delays processing by the specified number of nano seconds. 'delay_ns'
// must be less than the number of nano seconds in a second (1000000000).
void Delay(int delay_ns) {
  static const int kNumNSecInSecond = 1000000000;
  EXPECT_LT(delay_ns, kNumNSecInSecond);
  struct timespec delay = { 0, delay_ns };
  nanosleep(&delay, 0);
}

// Checks whether the profile timer is enabled for the current thread.
bool IsTimerEnabled() {
  itimerval current_timer;
  EXPECT_EQ(0, getitimer(timer_type_, &current_timer));
  if ((current_timer.it_value.tv_sec == 0) &&
      (current_timer.it_value.tv_usec != 0)) {
    // May be the timer has expired. Sleep for a bit and check again.
    Delay(kTimerResetInterval);
    EXPECT_EQ(0, getitimer(timer_type_, &current_timer));
  }
  return (current_timer.it_value.tv_sec != 0 ||
          current_timer.it_value.tv_usec != 0);
}

class VirtualTimerGetterThread : public Thread {
 public:
  VirtualTimerGetterThread() {
    memset(&virtual_timer_, 0, sizeof virtual_timer_);
  }
  struct itimerval virtual_timer_;

 private:
  void Run() {
    CHECK_EQ(0, getitimer(ITIMER_VIRTUAL, &virtual_timer_));
  }
};

// This function checks whether the timers are shared between thread. This
// function spawns a thread, so use it carefully when testing thread-dependent
// behaviour.
static bool threads_have_separate_timers() {
  struct itimerval new_timer_val;

  // Enable the virtual timer in the current thread.
  memset(&new_timer_val, 0, sizeof new_timer_val);
  new_timer_val.it_value.tv_sec = 1000000;  // seconds
  CHECK_EQ(0, setitimer(ITIMER_VIRTUAL, &new_timer_val, NULL));

  // Spawn a thread, get the virtual timer's value there.
  VirtualTimerGetterThread thread;
  thread.SetJoinable(true);
  thread.Start();
  thread.Join();

  // Disable timer here.
  memset(&new_timer_val, 0, sizeof new_timer_val);
  CHECK_EQ(0, setitimer(ITIMER_VIRTUAL, &new_timer_val, NULL));

  bool target_timer_enabled = (thread.virtual_timer_.it_value.tv_sec != 0 ||
                               thread.virtual_timer_.it_value.tv_usec != 0);
  if (!target_timer_enabled) {
    LOG(INFO, "threads have separate timers");
    return true;
  } else {
    LOG(INFO, "threads have shared timers");
    return false;
  }
}

// Dummy worker thread to accumulate cpu time.
class BusyThread : public Thread {
 public:
  BusyThread() : stop_work_(false) {
  }

  // Setter/Getters
  bool stop_work() {
    MutexLock lock(&mu_);
    return stop_work_;
  }
  void set_stop_work(bool stop_work) {
    MutexLock lock(&mu_);
    stop_work_ = stop_work;
  }

 private:
  // Protects stop_work_ below.
  Mutex mu_;
  // Whether to stop work?
  bool stop_work_;

  // Do work until asked to stop.
  void Run() {
    while (!stop_work()) {
    }
    // If timers are separate, check that timer is enabled for this thread.
    EXPECT_TRUE(!timer_separate_ || IsTimerEnabled());
  }
};

class NullThread : public Thread {
 private:
  void Run() {
    // If timers are separate, check that timer is enabled for this thread.
    EXPECT_TRUE(!timer_separate_ || IsTimerEnabled());
  }
};

// Signal handler which tracks the profile timer ticks.
static void TickCounter(int sig, siginfo_t* sig_info, void *vuc,
                        void* tick_counter) {
  int* counter = static_cast<int*>(tick_counter);
  ++(*counter);
}

// This class tests the profile-handler.h interface.
class ProfileHandlerTest {
 protected:

  // Determines whether threads have separate timers.
  static void SetUpTestCase() {
    timer_type_ = (getenv("CPUPROFILE_REALTIME") ? ITIMER_REAL : ITIMER_PROF);
    signal_number_ = (getenv("CPUPROFILE_REALTIME") ? SIGALRM : SIGPROF);

    timer_separate_ = threads_have_separate_timers();
    Delay(kTimerResetInterval);
  }

  // Sets up the profile timers and SIGPROF/SIGALRM handler in a known state.
  // It does the following:
  // 1. Unregisters all the callbacks, stops the timer (if shared) and
  //    clears out timer_sharing state in the ProfileHandler. This clears
  //    out any state left behind by the previous test or during module
  //    initialization when the test program was started.
  // 2. Spawns two threads which will be registered with the ProfileHandler.
  //    At this time ProfileHandler knows if the timers are shared.
  // 3. Starts a busy worker thread to accumulate CPU usage.
  virtual void SetUp() {
    // Reset the state of ProfileHandler between each test. This unregisters
    // all callbacks, stops timer (if shared) and clears timer sharing state.
    ProfileHandlerReset();
    EXPECT_EQ(0, GetCallbackCount());
    VerifyDisabled();
    // ProfileHandler requires at least two threads to be registerd to determine
    // whether timers are shared.
    RegisterThread();
    RegisterThread();
    // Now that two threads are started, verify that the signal handler is
    // disabled and the timers are correctly enabled/disabled.
    VerifyDisabled();
    // Start worker to accumulate cpu usage.
    StartWorker();
  }

  virtual void TearDown() {
    ProfileHandlerReset();
    // Stops the worker thread.
    StopWorker();
  }

  // Starts a no-op thread that gets registered with the ProfileHandler. Waits
  // for the thread to stop.
  void RegisterThread() {
    NullThread t;
    t.SetJoinable(true);
    t.Start();
    t.Join();
  }

  // Starts a busy worker thread to accumulate cpu time. There should be only
  // one busy worker running. This is required for the case where there are
  // separate timers for each thread.
  void StartWorker() {
    busy_worker_ = new BusyThread();
    busy_worker_->SetJoinable(true);
    busy_worker_->Start();
    // Wait for worker to start up and register with the ProfileHandler.
    // TODO(nabeelmian) This may not work under very heavy load.
    Delay(kSleepInterval);
  }

  // Stops the worker thread.
  void StopWorker() {
    busy_worker_->set_stop_work(true);
    busy_worker_->Join();
    delete busy_worker_;
  }

  // Checks whether SIGPROF/SIGALRM signal handler is enabled.
  bool IsSignalEnabled() {
    struct sigaction sa;
    CHECK_EQ(sigaction(signal_number_, NULL, &sa), 0);
    return ((sa.sa_handler == SIG_IGN) || (sa.sa_handler == SIG_DFL)) ?
        false : true;
  }

  // Gets the number of callbacks registered with the ProfileHandler.
  uint32 GetCallbackCount() {
    ProfileHandlerState state;
    ProfileHandlerGetState(&state);
    return state.callback_count;
  }

  // Gets the current ProfileHandler interrupt count.
  uint64 GetInterruptCount() {
    ProfileHandlerState state;
    ProfileHandlerGetState(&state);
    return state.interrupts;
  }

  // Verifies that a callback is correctly registered and receiving
  // profile ticks.
  void VerifyRegistration(const int& tick_counter) {
    // Check the callback count.
    EXPECT_GT(GetCallbackCount(), 0);
    // Check that the profile timer is enabled.
    EXPECT_EQ(FLAGS_test_profiler_enabled, IsTimerEnabled());
    // Check that the signal handler is enabled.
    if (FLAGS_test_profiler_signal_handler) {
      EXPECT_EQ(FLAGS_test_profiler_enabled, IsSignalEnabled());
    }
    uint64 interrupts_before = GetInterruptCount();
    // Sleep for a bit and check that tick counter is making progress.
    int old_tick_count = tick_counter;
    Delay(kSleepInterval);
    int new_tick_count = tick_counter;
    uint64 interrupts_after = GetInterruptCount();
    if (FLAGS_test_profiler_enabled) {
      EXPECT_GT(new_tick_count, old_tick_count);
      EXPECT_GT(interrupts_after, interrupts_before);
    } else {
      EXPECT_EQ(new_tick_count, old_tick_count);
      EXPECT_EQ(interrupts_after, interrupts_before);
    }
  }

  // Verifies that a callback is not receiving profile ticks.
  void VerifyUnregistration(const int& tick_counter) {
    // Sleep for a bit and check that tick counter is not making progress.
    int old_tick_count = tick_counter;
    Delay(kSleepInterval);
    int new_tick_count = tick_counter;
    EXPECT_EQ(old_tick_count, new_tick_count);
    // If no callbacks, signal handler and shared timer should be disabled.
    if (GetCallbackCount() == 0) {
      if (FLAGS_test_profiler_signal_handler) {
        EXPECT_FALSE(IsSignalEnabled());
      }
      if (timer_separate_) {
        EXPECT_TRUE(IsTimerEnabled());
      } else {
        EXPECT_FALSE(IsTimerEnabled());
      }
    }
  }

  // Verifies that the SIGPROF/SIGALRM interrupt handler is disabled and the
  // timer, if shared, is disabled. Expects the worker to be running.
  void VerifyDisabled() {
    // Check that the signal handler is disabled.
    if (FLAGS_test_profiler_signal_handler) {
      EXPECT_FALSE(IsSignalEnabled());
    }
    // Check that the callback count is 0.
    EXPECT_EQ(0, GetCallbackCount());
    // Check that the timer is disabled if shared, enabled otherwise.
    if (timer_separate_) {
      EXPECT_TRUE(IsTimerEnabled());
    } else {
      EXPECT_FALSE(IsTimerEnabled());
    }
    // Verify that the ProfileHandler is not accumulating profile ticks.
    uint64 interrupts_before = GetInterruptCount();
    Delay(kSleepInterval);
    uint64 interrupts_after = GetInterruptCount();
    EXPECT_EQ(interrupts_before, interrupts_after);
  }

  // Registers a callback and waits for kTimerResetInterval for timers to get
  // reset.
  ProfileHandlerToken* RegisterCallback(void* callback_arg) {
    ProfileHandlerToken* token = ProfileHandlerRegisterCallback(
        TickCounter, callback_arg);
    Delay(kTimerResetInterval);
    return token;
  }

  // Unregisters a callback and waits for kTimerResetInterval for timers to get
  // reset.
  void UnregisterCallback(ProfileHandlerToken* token) {
    ProfileHandlerUnregisterCallback(token);
    Delay(kTimerResetInterval);
  }

  // Busy worker thread to accumulate cpu usage.
  BusyThread* busy_worker_;

 private:
  // The tests to run
  void RegisterUnregisterCallback();
  void MultipleCallbacks();
  void Reset();
  void RegisterCallbackBeforeThread();

 public:
#define RUN(test)  do {                         \
    printf("Running %s\n", #test);              \
    ProfileHandlerTest pht;                     \
    pht.SetUp();                                \
    pht.test();                                 \
    pht.TearDown();                             \
} while (0)

  static int RUN_ALL_TESTS() {
    SetUpTestCase();
    RUN(RegisterUnregisterCallback);
    RUN(MultipleCallbacks);
    RUN(Reset);
    RUN(RegisterCallbackBeforeThread);
    printf("Done\n");
    return 0;
  }
};

// Verifies ProfileHandlerRegisterCallback and
// ProfileHandlerUnregisterCallback.
TEST_F(ProfileHandlerTest, RegisterUnregisterCallback) {
  int tick_count = 0;
  ProfileHandlerToken* token = RegisterCallback(&tick_count);
  VerifyRegistration(tick_count);
  UnregisterCallback(token);
  VerifyUnregistration(tick_count);
}

// Verifies that multiple callbacks can be registered.
TEST_F(ProfileHandlerTest, MultipleCallbacks) {
  // Register first callback.
  int first_tick_count;
  ProfileHandlerToken* token1 = RegisterCallback(&first_tick_count);
  // Check that callback was registered correctly.
  VerifyRegistration(first_tick_count);
  EXPECT_EQ(1, GetCallbackCount());

  // Register second callback.
  int second_tick_count;
  ProfileHandlerToken* token2 = RegisterCallback(&second_tick_count);
  // Check that callback was registered correctly.
  VerifyRegistration(second_tick_count);
  EXPECT_EQ(2, GetCallbackCount());

  // Unregister first callback.
  UnregisterCallback(token1);
  VerifyUnregistration(first_tick_count);
  EXPECT_EQ(1, GetCallbackCount());
  // Verify that second callback is still registered.
  VerifyRegistration(second_tick_count);

  // Unregister second callback.
  UnregisterCallback(token2);
  VerifyUnregistration(second_tick_count);
  EXPECT_EQ(0, GetCallbackCount());

  // Verify that the signal handler and timers are correctly disabled.
  VerifyDisabled();
}

// Verifies ProfileHandlerReset
TEST_F(ProfileHandlerTest, Reset) {
  // Verify that the profile timer interrupt is disabled.
  VerifyDisabled();
  int first_tick_count;
  RegisterCallback(&first_tick_count);
  VerifyRegistration(first_tick_count);
  EXPECT_EQ(1, GetCallbackCount());

  // Register second callback.
  int second_tick_count;
  RegisterCallback(&second_tick_count);
  VerifyRegistration(second_tick_count);
  EXPECT_EQ(2, GetCallbackCount());

  // Reset the profile handler and verify that callback were correctly
  // unregistered and timer/signal are disabled.
  ProfileHandlerReset();
  VerifyUnregistration(first_tick_count);
  VerifyUnregistration(second_tick_count);
  VerifyDisabled();
}

// Verifies that ProfileHandler correctly handles a case where a callback was
// registered before the second thread started.
TEST_F(ProfileHandlerTest, RegisterCallbackBeforeThread) {
  // Stop the worker.
  StopWorker();
  // Unregister all existing callbacks, stop the timer (if shared), disable
  // the signal handler and reset the timer sharing state in the Profile
  // Handler.
  ProfileHandlerReset();
  EXPECT_EQ(0, GetCallbackCount());
  VerifyDisabled();

  // Start the worker. At this time ProfileHandler doesn't know if timers are
  // shared as only one thread has registered so far.
  StartWorker();
  // Register a callback and check that profile ticks are being delivered.
  int tick_count;
  RegisterCallback(&tick_count);
  EXPECT_EQ(1, GetCallbackCount());
  VerifyRegistration(tick_count);

  // Register a second thread and verify that timer and signal handler are
  // correctly enabled.
  RegisterThread();
  EXPECT_EQ(1, GetCallbackCount());
  EXPECT_EQ(FLAGS_test_profiler_enabled, IsTimerEnabled());
  if (FLAGS_test_profiler_signal_handler) {
    EXPECT_EQ(FLAGS_test_profiler_enabled, IsSignalEnabled());
  }
}

}  // namespace

int main(int argc, char** argv) {
  return ProfileHandlerTest::RUN_ALL_TESTS();
}

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