[not for commit] V8 profiler API preview.

include/v8-profiler.h

Index: include/v8-profiler.h
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+// Copyright 2010 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef V8_V8_PROFILER_H_
+#define V8_V8_PROFILER_H_
+
+#include "v8.h"
+
+#ifdef _WIN32
+// Setup for Windows DLL export/import. See v8.h in this directory for
+// information on how to build/use V8 as a DLL.
+#if defined(BUILDING_V8_SHARED) && defined(USING_V8_SHARED)
+#error both BUILDING_V8_SHARED and USING_V8_SHARED are set - please check the\
+  build configuration to ensure that at most one of these is set
+#endif
+
+#ifdef BUILDING_V8_SHARED
+#define V8EXPORT __declspec(dllexport)
+#elif USING_V8_SHARED
+#define V8EXPORT __declspec(dllimport)
+#else
+#define V8EXPORT
+#endif
+
+#else  // _WIN32
+
+// Setup for Linux shared library export. See v8.h in this directory for
+// information on how to build/use V8 as shared library.
+#if defined(__GNUC__) && (__GNUC__ >= 4) && defined(V8_SHARED)
+#define V8EXPORT __attribute__ ((visibility("default")))
+#else  // defined(__GNUC__) && (__GNUC__ >= 4)
+#define V8EXPORT
+#endif  // defined(__GNUC__) && (__GNUC__ >= 4)
+
+#endif  // _WIN32
+
+
+/**
+ * Profiler support for the V8 JavaScript engine.
+ */
+namespace v8 {
+
+
+/**
+ * CpuProfileNode represents a node in a call graph.
+ */
+class V8EXPORT CpuProfileNode {
+ public:
+  /** Returns function name (empty string for anonymous functions.) */
+  Handle<String> GetFunctionName() const;
+
+  /** Returns resource name for script from where the function originates. */
+  Handle<Value> GetScriptResourceName() const;
+
+  /**
+   * Returns the number, 1-based, of the line where the function originates.
+   * 0 means that no line number information is available.
+   */
+  int GetLineNumber() const;
+
+  /**
+   * Returns total (self + children) execution time of the function,
+   * in milliseconds, estimated by samples count.
+   */
+  double GetTotalTime() const;
+
+  /**
+   * Returns self execution time of the function, in milliseconds,
+   * estimated by samples count.
+   */
+  double GetSelfTime() const;
+
+  /** Returns the count of samples where function exists. */
+  double GetTotalSamplesCount() const;
+
+  /** Returns the count of samples where function was currently executing. */
+  double GetSelfSamplesCount() const;
+
+  /** Returns child nodes count of the node. */
+  int GetChildrenCount() const;
+
+  /** Retrieves a child node by index. */
+  Handle<CpuProfileNode> GetChild(int index) const;
+};
+
+
+/**
+ * CpuProfile contains a CPU profile in a form of 2 call trees:

[Mads Ager (chromium), 2010/03/23 08:38:26]

in a form -> in form
2 -> two?

+ *  - top-down (from main() down to functions that do all the work);
+ *  - bottom-up call graph (in backward direction).
+ */
+class V8EXPORT CpuProfile {
+ public:
+  /** Returns CPU profile UID (assigned by the profiler.) */
+  unsigned GetUid(); const;
+
+  /** Returns CPU profile title. */
+  Handle<String> GetTitle() const;
+
+  /** Returns the root node of the bottom up call tree. */
+  Handle<CpuProfileNode> GetBottomUpRoot() const;
+
+  /** Returns the root node of the top down call tree. */
+  Handle<CpuProfileNode> GetTopDownRoot() const;
+};

[zundel, 2010/03/26 13:49:15]

One thing I love about the v8 profiling data is that it classifies time by VM
state (compiling, garbage collection, etc).  Do you anticipate a way of exposing
that information?

+
+
+/**
+ * Interface for controlling CPU profiling in V8.
+ */
+class V8EXPORT CpuProfiler {
+ public:
+  /**
+   * Returns the number of profiles collected (doesn't include
+   * profiles that are being collected at the moment of call.)
+   */
+  static int GetProfilesCount();
+
+  /** Returns a profile by index. */
+  static Handle<CpuProfile> GetProfile(int index);
+
+  /** Returns a profile by uid. */
+  static Handle<CpuProfile> GetProfile(unsigned uid);
+
+  /**
+   * Starts collecting CPU profile. It is possible to have several
+   * collected profiles at once.  Attempts to start collecting several
+   * profiles with the same title are silently ignored. */

[Mads Ager (chromium), 2010/03/23 08:38:26]

Move '*/' to next line.

[zundel, 2010/03/26 12:53:33]

Does this comment mean that you can start different profiles and have them
accumulating simultaneously?  

start profile1 at time T1
start profile2 at time T2
stop profile2 at time T3
stop profile1 at time T4

so that profile2 is profiling a subset of profile1?

[zundel, 2010/03/26 13:49:15]

Should this function return a uid for use in GetProfile(uid) ?

+  static void StartProfiling(Handle<String> title = Handle<String>());

[zundel, 2010/03/26 13:49:15]

for starting/stopping profiles automatically, I don't care so much about the
names (they aren't going to be ready by a human).  Could we come up with a way
for a unique name be assigned automatically?  Same with stopping the profile.  I
would want some kind of handle (uid?) returned from StartProfile to use to turn
this one off.

+
+  /**
+   * Stops collecting CPU profile with a given title. If no title is
+   * given, finishes the last profile started.
+   */
+  static void StopProfiling(Handle<String> title = Handle<String>());
+};
+
+
+}  // namespace v8
+
+
+#undef V8EXPORT
+
+
+#endif  // V8_V8_PROFILER_H_