Introduce a CompilerDispatcherTracer and track how long jobs take

src/compiler-dispatcher/compiler-dispatcher-tracer.h

Index: src/compiler-dispatcher/compiler-dispatcher-tracer.h
diff --git a/src/compiler-dispatcher/compiler-dispatcher-tracer.h b/src/compiler-dispatcher/compiler-dispatcher-tracer.h
new file mode 100644
index 0000000000000000000000000000000000000000..f0f87e1ffe6b83298478271573b80308421f9797
--- /dev/null
+++ b/src/compiler-dispatcher/compiler-dispatcher-tracer.h
@@ -0,0 +1,97 @@
+// Copyright 2016 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef V8_COMPILER_DISPATCHER_COMPILER_DISPATCHER_TRACER_H_
+#define V8_COMPILER_DISPATCHER_COMPILER_DISPATCHER_TRACER_H_
+
+#include <utility>
+
+#include "src/base/macros.h"
+#include "src/base/platform/mutex.h"
+#include "src/base/ring-buffer.h"
+#include "src/counters.h"
+
+namespace v8 {
+namespace internal {
+
+class Isolate;
+class RuntimeCallStats;
+
+#define COMPILER_DISPATCHER_TRACE_SCOPE_WITH_NUM(tracer, scope_id, num)      \
+  CompilerDispatcherTracer::ScopeID tracer_scope_id(                         \
+      CompilerDispatcherTracer::ScopeID::scope_id);                          \
+  CompilerDispatcherTracer::Scope trace_scope(tracer, tracer_scope_id, num); \
+  TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("v8.compile"),                      \
+               CompilerDispatcherTracer::Scope::Name(tracer_scope_id))
+
+#define COMPILER_DISPATCHER_TRACE_SCOPE(tracer, scope_id) \
+  COMPILER_DISPATCHER_TRACE_SCOPE_WITH_NUM(tracer, scope_id, 0)
+
+class CompilerDispatcherTracer {
+ public:
+  enum class ScopeID {
+    kPrepareToParse,
+    kParse,
+    kFinalizeParsing,
+    kPrepareToCompile,
+    kCompile,
+    kFinalizeCompiling
+  };
+
+  class Scope {
+   public:
+    Scope(CompilerDispatcherTracer* tracer, ScopeID scope_id, size_t num = 0);
+    ~Scope();
+
+    static const char* Name(ScopeID scoped_id);
+
+   private:
+    CompilerDispatcherTracer* tracer_;
+    ScopeID scope_id_;
+    size_t num_;
+    double start_time_;
+    RuntimeCallTimer timer_;
+
+    DISALLOW_COPY_AND_ASSIGN(Scope);
+  };
+
+  explicit CompilerDispatcherTracer(Isolate* isolate);
+  ~CompilerDispatcherTracer();
+
+  void RecordPrepareToParse(double duration_ms);
+  void RecordParse(double duration_ms, size_t source_length);
+  void RecordFinalizeParsing(double duration_ms);
+  void RecordPrepareToCompile(double duration_ms);
+  void RecordCompile(double duration_ms, size_t ast_size_in_bytes);
+  void RecordFinalizeCompiling(double duration_ms);
+
+  double EstimatePrepareToParseInMs() const;
+  double EstimateParseInMs(size_t source_length) const;
+  double EstimateFinalizeParsingInMs();
+  double EstimatePrepareToCompileInMs();
+  double EstimateCompileInMs(size_t ast_size_in_bytes);
+  double EstimateFinalizeCompilingInMs();
+
+ private:
+  static double Average(const base::RingBuffer<double>& buffer);
+  static double Estimate(
+      const base::RingBuffer<std::pair<size_t, double>>& buffer, size_t num);
+
+  mutable base::Mutex mutex_;
+  base::RingBuffer<double> prepare_parse_events_;
+  base::RingBuffer<std::pair<size_t, double>> parse_events_;
+  base::RingBuffer<double> finalize_parsing_events_;
+  base::RingBuffer<double> prepare_compile_events_;
+  base::RingBuffer<std::pair<size_t, double>> compile_events_;
+  base::RingBuffer<double> finalize_compiling_events_;
+
+  RuntimeCallStats* runtime_call_stats_;
+
+  DISALLOW_COPY_AND_ASSIGN(CompilerDispatcherTracer);
+};
+
+}  // namespace internal
+}  // namespace v8
+
+#endif  // V8_COMPILER_DISPATCHER_COMPILER_DISPATCHER_TRACER_H_