Profiler Take 2

runtime/vm/profiler_macos.cc

-// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-#include "platform/globals.h"
-#if defined(TARGET_OS_MACOS)
-
-#include "vm/isolate.h"
-#include "vm/json_stream.h"
-#include "vm/profiler.h"
-#include "vm/signal_handler.h"
-
-namespace dart {
-
-DECLARE_FLAG(bool, profile);
-DECLARE_FLAG(bool, trace_profiled_isolates);
-
-static void CollectSample(IsolateProfilerData* profiler_data,
-                          uintptr_t pc,
-                          uintptr_t fp,
-                          uintptr_t sp,
-                          uintptr_t stack_lower,
-                          uintptr_t stack_upper) {
-  SampleBuffer* sample_buffer = profiler_data->sample_buffer();
-  Sample* sample = sample_buffer->ReserveSample();
-  ASSERT(sample != NULL);
-  sample->timestamp = OS::GetCurrentTimeMicros();
-  // TODO(johnmccutchan): Make real use of vm_tags and runtime_tags.
-  // Issue # 14777
-  sample->vm_tags = Sample::kExecuting;
-  sample->runtime_tags = 0;
-  int64_t cpu_usage = 0;
-  Thread::GetThreadCpuUsage(profiler_data->thread_id(), &cpu_usage);
-  sample->cpu_usage = profiler_data->ComputeDeltaAndSetCpuUsage(cpu_usage);
-  ProfilerSampleStackWalker stackWalker(sample, stack_lower, stack_upper,
-                                        pc, fp, sp);
-  stackWalker.walk();
-}
-
-
-static void ProfileSignalAction(int signal, siginfo_t* info, void* context_) {
-  if (signal != SIGPROF) {
-    return;
-  }
-  ucontext_t* context = reinterpret_cast<ucontext_t*>(context_);
-  mcontext_t mcontext = context->uc_mcontext;
-  Isolate* isolate = Isolate::Current();
-  if (isolate == NULL) {
-    return;
-  }
-  // Thread owns no profiler locks at this point.
-  {
-    // Thread owns isolate profiler data mutex.
-    ScopedMutex profiler_data_lock(isolate->profiler_data_mutex());
-    IsolateProfilerData* profiler_data = isolate->profiler_data();
-    if ((profiler_data == NULL) || !profiler_data->CanExpire() ||
-        (profiler_data->sample_buffer() == NULL)) {
-      // Descheduled.
-      return;
-    }
-    if (profiler_data->thread_id() == Thread::GetCurrentThreadId()) {
-      // Still scheduled on this thread.
-      uintptr_t stack_lower = 0;
-      uintptr_t stack_upper = 0;
-      isolate->GetStackBounds(&stack_lower, &stack_upper);
-      uintptr_t PC = SignalHandler::GetProgramCounter(mcontext);
-      uintptr_t FP = SignalHandler::GetFramePointer(mcontext);
-      uintptr_t SP = SignalHandler::GetStackPointer(mcontext);
-      int64_t sample_time = OS::GetCurrentTimeMicros();
-      profiler_data->SampledAt(sample_time);
-      CollectSample(profiler_data, PC, FP, SP, stack_lower, stack_upper);
-    }
-  }
-  // Thread owns no profiler locks at this point.
-  // This call will acquire both ProfilerManager::monitor and the
-  // isolate's profiler data mutex.
-  ProfilerManager::ScheduleIsolate(isolate, true);
-}
-
-
-int64_t ProfilerManager::SampleAndRescheduleIsolates(int64_t current_time) {
-  if (isolates_size_ == 0) {
-    return 0;
-  }
-  static const int64_t max_time = 0x7fffffffffffffffLL;
-  int64_t lowest = max_time;
-  intptr_t i = 0;
-  while (i < isolates_size_) {
-    Isolate* isolate = isolates_[i];
-    ScopedMutex isolate_lock(isolate->profiler_data_mutex());
-    IsolateProfilerData* profiler_data = isolate->profiler_data();
-    if (profiler_data == NULL) {
-      // Isolate has been shutdown for profiling.
-      RemoveIsolate(i);
-      // Remove moves the last element into i, do not increment i.
-      continue;
-    }
-    ASSERT(profiler_data != NULL);
-    if (profiler_data->ShouldSample(current_time)) {
-      pthread_kill(profiler_data->thread_id(), SIGPROF);
-      RemoveIsolate(i);
-      // Remove moves the last element into i, do not increment i.
-      continue;
-    }
-    if (profiler_data->CanExpire()) {
-      int64_t isolate_time_left =
-          profiler_data->TimeUntilExpiration(current_time);
-      if (isolate_time_left < 0) {
-        continue;
-      }
-      if (isolate_time_left < lowest) {
-        lowest = isolate_time_left;
-      }
-    }
-    i++;
-  }
-  if (isolates_size_ == 0) {
-    return 0;
-  }
-  if (lowest == max_time) {
-    return 0;
-  }
-  ASSERT(lowest != max_time);
-  ASSERT(lowest > 0);
-  return lowest;
-}
-
-
-void ProfilerManager::ThreadMain(uword parameters) {
-  ASSERT(initialized_);
-  ASSERT(FLAG_profile);
-  SignalHandler::Install(ProfileSignalAction);
-  if (FLAG_trace_profiled_isolates) {
-    OS::Print("ProfilerManager MacOS ready.\n");
-  }
-  {
-    // Signal to main thread we are ready.
-    ScopedMonitor startup_lock(start_stop_monitor_);
-    thread_running_ = true;
-    startup_lock.Notify();
-  }
-  ScopedMonitor lock(monitor_);
-  while (!shutdown_) {
-    int64_t current_time = OS::GetCurrentTimeMicros();
-    int64_t next_sample = SampleAndRescheduleIsolates(current_time);
-    lock.WaitMicros(next_sample);
-  }
-  if (FLAG_trace_profiled_isolates) {
-    OS::Print("ProfilerManager MacOS exiting.\n");
-  }
-  {
-    // Signal to main thread we are exiting.
-    ScopedMonitor shutdown_lock(start_stop_monitor_);
-    thread_running_ = false;
-    shutdown_lock.Notify();
-  }
-}
-
-
-}  // namespace dart
-
-#endif  // defined(TARGET_OS_MACOS)