Sampling profiler

runtime/vm/profiler_win.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_WINDOWS)
+
+#include "vm/isolate.h"
+#include "vm/profiler.h"
+
+namespace dart {
+
+#define kThreadError -1
+
+DECLARE_FLAG(bool, profile);
+
+static void CollectSample(IsolateProfilerData* profiler_data,
+                          uintptr_t pc,
+                          uintptr_t fp,
+                          uintptr_t stack_lower,
+                          uintptr_t stack_upper) {
+  uintptr_t sp = stack_lower;
+  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;
+  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 bool GrabRegisters(ThreadId thread, uintptr_t* pc, uintptr_t* fp,
+                          uintptr_t* sp) {
+  CONTEXT context;
+  memset(&context, 0, sizeof(context));
+  context.ContextFlags = CONTEXT_FULL;
+  if (GetThreadContext(thread, &context) != 0) {
+#if defined(TARGET_ARCH_IA32)
+    *pc = static_cast<uintptr_t>(context.Eip);
+    *fp = static_cast<uintptr_t>(context.Ebp);
+    *sp = static_cast<uintptr_t>(context.Esp);
+#elif defined(TARGET_ARCH_X64)
+    *pc = reinterpret_cast<uintptr_t>(context.Rip);
+    *fp = reinterpret_cast<uintptr_t>(context.Rbp);
+    *sp = reinterpret_cast<uintptr_t>(context.Rsp);
+#else
+    UNIMPLEMENTED();
+#endif
+    return true;
+  }
+  return false;
+}
+
+
+static void SuspendAndSample(Isolate* isolate,
+                             IsolateProfilerData* profiler_data) {
+  ASSERT(GetCurrentThread() != profiler_data->thread_id());
+  DWORD result = SuspendThread(profiler_data->thread_id());
+  if (result == kThreadError) {
+    return;
+  }
+  uintptr_t PC;
+  uintptr_t FP;
+  uintptr_t stack_lower;
+  uintptr_t stack_upper;
+  bool r = isolate->GetStackBounds(&stack_lower, &stack_upper);
+  if (r) {
+    r = GrabRegisters(profiler_data->thread_id(), &PC, &FP, &stack_lower);
+    if (r) {
+      int64_t sample_time = OS::GetCurrentTimeMicros();
+      profiler_data->SampledAt(sample_time);
+      CollectSample(profiler_data, PC, FP, stack_lower, stack_upper);
+    }
+  }
+
+  ResumeThread(profiler_data->thread_id());
+}
+
+
+static void Reschedule(IsolateProfilerData* profiler_data) {
+  profiler_data->Scheduled(OS::GetCurrentTimeMicros(),
+                           profiler_data->thread_id());
+}
+
+
+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;
+  for (intptr_t i = 0; i < isolates_size_; i++) {
+    Isolate* isolate = isolates_[i];
+    ScopedMutex isolate_lock(isolate->profiler_data_mutex());
+    IsolateProfilerData* profiler_data = isolate->profiler_data();
+    ASSERT(profiler_data != NULL);
+    if (profiler_data->ShouldSample(current_time)) {
+      SuspendAndSample(isolate, profiler_data);
+      Reschedule(profiler_data);
+    }
+    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;
+      }
+    }
+  }
+  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);
+  ScopedMonitor lock(monitor_);
+  while (!shutdown_) {
+    int64_t current_time = OS::GetCurrentTimeMicros();
+    int64_t next_sample = SampleAndRescheduleIsolates(current_time);
+    lock.WaitMicros(next_sample);
+  }
+}
+
+}  // namespace dart
+
+#endif  // defined(TARGET_OS_WINDOWS)