v8/include/v8-profiler.h
mikhail.naganov@gmail.com c98ac6e82c Heap profiler: implement diffing of snapshots.
To trace objects between snapshots, an external map of object tags is
maintained. After the first heap snapshot has been taken, the map is
updated by reporting object moves from the GC. If no snapshots were
taken, there is no overhead (except for flag checking).

I considered graph comparison algorithms that doesn't require using
object tags, but they are all of a high computational complexity, and
will still fail to detect object moves properly, even for trivial
cases, so using tags looks like unavoidable.

Review URL: http://codereview.chromium.org/3020002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5078 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2010-07-15 13:21:50 +00:00

354 lines
10 KiB
C++

// 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<String> GetScriptResourceName() const;
/**
* Returns the number, 1-based, of the line where the function originates.
* kNoLineNumberInfo if 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 function entry UID. */
unsigned GetCallUid() const;
/** Returns child nodes count of the node. */
int GetChildrenCount() const;
/** Retrieves a child node by index. */
const CpuProfileNode* GetChild(int index) const;
static const int kNoLineNumberInfo = Message::kNoLineNumberInfo;
};
/**
* CpuProfile contains a CPU profile in a form of two call trees:
* - 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. */
const CpuProfileNode* GetBottomUpRoot() const;
/** Returns the root node of the top down call tree. */
const CpuProfileNode* GetTopDownRoot() const;
};
/**
* Interface for controlling CPU profiling.
*/
class V8EXPORT CpuProfiler {
public:
/**
* A note on security tokens usage. As scripts from different
* origins can run inside a single V8 instance, it is possible to
* have functions from different security contexts intermixed in a
* single CPU profile. To avoid exposing function names belonging to
* other contexts, filtering by security token is performed while
* obtaining profiling results.
*/
/**
* 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 const CpuProfile* GetProfile(
int index,
Handle<Value> security_token = Handle<Value>());
/** Returns a profile by uid. */
static const CpuProfile* FindProfile(
unsigned uid,
Handle<Value> security_token = Handle<Value>());
/**
* Starts collecting CPU profile. Title may be an empty string. It
* is allowed to have several profiles being collected at
* once. Attempts to start collecting several profiles with the same
* title are silently ignored. While collecting a profile, functions
* from all security contexts are included in it. The token-based
* filtering is only performed when querying for a profile.
*/
static void StartProfiling(Handle<String> title);
/**
* Stops collecting CPU profile with a given title and returns it.
* If the title given is empty, finishes the last profile started.
*/
static const CpuProfile* StopProfiling(
Handle<String> title,
Handle<Value> security_token = Handle<Value>());
};
class HeapGraphNode;
/**
* HeapSnapshotEdge represents a directed connection between heap
* graph nodes: from retaners to retained nodes.
*/
class V8EXPORT HeapGraphEdge {
public:
enum Type {
CONTEXT_VARIABLE = 0, // A variable from a function context.
ELEMENT = 1, // An element of an array.
PROPERTY = 2, // A named object property.
INTERNAL = 3 // A link that can't be accessed from JS,
// thus, its name isn't a real property name.
};
/** Returns edge type (see HeapGraphEdge::Type). */
Type GetType() const;
/**
* Returns edge name. This can be a variable name, an element index, or
* a property name.
*/
Handle<Value> GetName() const;
/** Returns origin node. */
const HeapGraphNode* GetFromNode() const;
/** Returns destination node. */
const HeapGraphNode* GetToNode() const;
};
class V8EXPORT HeapGraphPath {
public:
/** Returns the number of edges in the path. */
int GetEdgesCount() const;
/** Returns an edge from the path. */
const HeapGraphEdge* GetEdge(int index) const;
/** Returns origin node. */
const HeapGraphNode* GetFromNode() const;
/** Returns destination node. */
const HeapGraphNode* GetToNode() const;
};
/**
* HeapGraphNode represents a node in a heap graph.
*/
class V8EXPORT HeapGraphNode {
public:
enum Type {
INTERNAL = 0, // Internal node, a virtual one, for housekeeping.
ARRAY = 1, // An array of elements.
STRING = 2, // A string.
OBJECT = 3, // A JS object (except for arrays and strings).
CODE = 4, // Compiled code.
CLOSURE = 5 // Function closure.
};
/** Returns node type (see HeapGraphNode::Type). */
Type GetType() const;
/**
* Returns node name. Depending on node's type this can be the name
* of the constructor (for objects), the name of the function (for
* closures), string value, or an empty string (for compiled code).
*/
Handle<String> GetName() const;
/**
* Returns node id. For the same heap object, the id remains the same
* across all snapshots.
*/
uint64_t GetId() const;
/** Returns node's own size, in bytes. */
int GetSelfSize() const;
/** Returns node's network (self + reachable nodes) size, in bytes. */
int GetTotalSize() const;
/**
* Returns node's private size, in bytes. That is, the size of memory
* that will be reclaimed having this node collected.
*/
int GetPrivateSize() const;
/** Returns child nodes count of the node. */
int GetChildrenCount() const;
/** Retrieves a child by index. */
const HeapGraphEdge* GetChild(int index) const;
/** Returns retainer nodes count of the node. */
int GetRetainersCount() const;
/** Returns a retainer by index. */
const HeapGraphEdge* GetRetainer(int index) const;
/** Returns the number of simple retaining paths from the root to the node. */
int GetRetainingPathsCount() const;
/** Returns a retaining path by index. */
const HeapGraphPath* GetRetainingPath(int index) const;
};
class V8EXPORT HeapSnapshotsDiff {
public:
/** Returns the root node for added nodes. */
const HeapGraphNode* GetAdditionsRoot() const;
/** Returns the root node for deleted nodes. */
const HeapGraphNode* GetDeletionsRoot() const;
};
/**
* HeapSnapshots record the state of the JS heap at some moment.
*/
class V8EXPORT HeapSnapshot {
public:
/** Returns heap snapshot UID (assigned by the profiler.) */
unsigned GetUid() const;
/** Returns heap snapshot title. */
Handle<String> GetTitle() const;
/** Returns the root node of the heap graph. */
const HeapGraphNode* GetRoot() const;
/** Returns a diff between this snapshot and another one. */
const HeapSnapshotsDiff* CompareWith(const HeapSnapshot* snapshot) const;
};
/**
* Interface for controlling heap profiling.
*/
class V8EXPORT HeapProfiler {
public:
/** Returns the number of snapshots taken. */
static int GetSnapshotsCount();
/** Returns a snapshot by index. */
static const HeapSnapshot* GetSnapshot(int index);
/** Returns a profile by uid. */
static const HeapSnapshot* FindSnapshot(unsigned uid);
/** Takes a heap snapshot and returns it. Title may be an empty string. */
static const HeapSnapshot* TakeSnapshot(Handle<String> title);
};
} // namespace v8
#undef V8EXPORT
#endif // V8_V8_PROFILER_H_