对nodejs进行profiling
想在服务器上捣腾一下node.js，编译的时候加了--profile参数，想要开启profile功能，安装了node.js后，运行 nodejs --prof {js文件} 可以得到一个v8.log文件，但是到 {nodejs代码}/deps/v8/tools 目录下运行 linux-tick-processor {v8.log文件} 的时候，提示：
d8 shell not found in . To build, execute 'sconsd8' from the V8 directory
上网搜了一圈，最后按以下步骤成功编译了d8 shell，并正常使用linux-tick-processor：
- cd {nodejs代码}/deps/v8
- scons prof=on
- scons d8
- 把目录 {nodejs代码}/deps/v8 加入PATH环境变量
按以上步骤配置后，就可以用 nodejs --prof {js文件} 的方式运行，并获得一个v8.log文件，然后到 {nodejs代码}/deps/v8/tools 目录下运行 linux-tick-processor {v8.log文件}，就可以得到类似这样的输出结果：
Statistical profiling result from ../../../v8.log, (82093 ticks, 0 unaccounted, 0 excluded).
[Shared libraries]:
ticks total nonlib name
3 0.0% 0.0% /lib/x86_64-linux-gnu/libc-2.13.so
2 0.0% 0.0% /lib/x86_64-linux-gnu/libpthread-2.13.so
[JavaScript]:
ticks total nonlib name
1 0.0% 0.0% Stub: InstanceofStub
1 0.0% 0.0% Builtin: A builtin from the snapshot
[C++]:
ticks total nonlib name
81995 99.9% 99.9% epoll_wait
15 0.0% 0.0% __write
11 0.0% 0.0% node::WrappedScript::CompileRunInThisContext(v8::Arguments const&)
5 0.0% 0.0% node::Parser::Execute(v8::Arguments const&)
4 0.0% 0.0% v8::internal::RelocIterator::next()
4 0.0% 0.0% _IO_vfprintf
2 0.0% 0.0% v8::internal::UpdatingVisitor::VisitPointers(v8::internal::Object**, v8::internal::Object**)
2 0.0% 0.0% v8::internal::StaticMarkingVisitor::VisitUnmarkedObjects(v8::internal::Heap*, v8::internal::Object**, v8::internal::Object**)
2 0.0% 0.0% v8::internal::Parser::ParseMemberWithNewPrefixesExpression(v8::internal::PositionStack*, bool*)
2 0.0% 0.0% node::Binding(v8::Arguments const&)
1 0.0% 0.0% v8::internal::Zone::New(int)
1 0.0% 0.0% v8::internal::UpdatingVisitor::VisitPointer(v8::internal::Object**)
1 0.0% 0.0% v8::internal::TextNode::EatsAtLeast(int, int, bool)
1 0.0% 0.0% v8::internal::StubCache::ComputeKeyedLoadField(v8::internal::String*, v8::internal::JSObject*, v8::internal::JSObject*, int)
1 0.0% 0.0% v8::internal::String::IsAsciiEqualTo(v8::internal::Vector)
1 0.0% 0.0% v8::internal::StaticMarkingVisitor::VisitSharedFunctionInfoAndFlushCode(v8::internal::Map*, v8::internal::HeapObject*)
1 0.0% 0.0% v8::internal::StaticMarkingVisitor::VisitCode(v8::internal::Map*, v8::internal::HeapObject*)
1 0.0% 0.0% v8::internal::Scope::LookupRecursive(v8::internal::Handle, bool, v8::internal::Variable**)
1 0.0% 0.0% v8::internal::RelocInfoWriter::Write(v8::internal::RelocInfo const*)
1 0.0% 0.0% v8::internal::Parser::ParseStatement(v8::internal::ZoneList >*, bool*)
1 0.0% 0.0% v8::internal::Parser::ParseLeftHandSideExpression(bool*)
1 0.0% 0.0% v8::internal::Parser::ParseLazy(v8::internal::CompilationInfo*, v8::internal::UC16CharacterStream*, v8::internal::ZoneScope*)
1 0.0% 0.0% v8::internal::OldSpace::PrepareForMarkCompact(bool)
1 0.0% 0.0% v8::internal::OldSpace::PageAllocationLimit(v8::internal::Page*)
1 0.0% 0.0% v8::internal::MemoryAllocator::InitializePagesInChunk(int, int, v8::internal::PagedSpace*)
1 0.0% 0.0% v8::internal::MarkCompactCollector::UpdatePointersInOldObject(v8::internal::HeapObject*)
1 0.0% 0.0% v8::internal::MarkCompactCollector::RelocateCodeObject(v8::internal::HeapObject*)
1 0.0% 0.0% v8::internal::MacroAssembler::InvokeFunction(v8::internal::JSFunction*, v8::internal::ParameterCount const&, InvokeFlag, v8::internal::CallWrapper const&, v8::internal::CallKind)
1 0.0% 0.0% v8::internal::LoadStubCompiler::CompileLoadField(v8::internal::JSObject*, v8::internal::JSObject*, int, v8::internal::String*)
1 0.0% 0.0% v8::internal::LargeObjectSpace::Contains(v8::internal::HeapObject*)
1 0.0% 0.0% v8::internal::LargeObjectChunk::New(int, v8::internal::Executability)
1 0.0% 0.0% v8::internal::LAllocator::LiveRangeFor(int)
1 0.0% 0.0% v8::internal::JavaScriptScanner::SkipSingleLineComment()
1 0.0% 0.0% v8::internal::JavaScriptScanner::ScanIdentifierOrKeyword()
1 0.0% 0.0% v8::internal::JavaScriptScanner::Scan()
1 0.0% 0.0% v8::internal::JavaScriptScanner::Next()
1 0.0% 0.0% v8::internal::JSReceiver::LocalLookup(v8::internal::String*, v8::internal::LookupResult*)
1 0.0% 0.0% v8::internal::IC::Clear(unsigned char*)
1 0.0% 0.0% v8::internal::Heap::DoScavenge(v8::internal::ObjectVisitor*, unsigned char*)
1 0.0% 0.0% v8::internal::Heap::AllocateRaw(int, v8::internal::AllocationSpace, v8::internal::AllocationSpace)
1 0.0% 0.0% v8::internal::FullCodeGenerator::StackValueContext::Plug(v8::internal::Variable*) const
1 0.0% 0.0% v8::internal::FullCodeGenerator::EmitClassOf(v8::internal::ZoneList*)
1 0.0% 0.0% v8::internal::FlexibleBodyVisitor::Visit(v8::internal::Map*, v8::internal::HeapObject*)
1 0.0% 0.0% v8::internal::CallICBase::ReceiverToObjectIfRequired(v8::internal::Handle, v8::internal::Handle)
1 0.0% 0.0% v8::internal::Assembler::movq(v8::internal::Register, v8::internal::Operand const&)
1 0.0% 0.0% v8::internal::Assembler::call(v8::internal::Handle, v8::internal::RelocInfo::Mode, unsigned int)
1 0.0% 0.0% node::TCPWrap::OnConnection(uv_stream_s*, int)
1 0.0% 0.0% node::HandleWrap::Close(v8::Arguments const&)
1 0.0% 0.0% __pthread_mutex_lock
1 0.0% 0.0% __libc_free
1 0.0% 0.0% _ZN2v88internal8JSObject11LocalLookupEPNS0_6StringEPNS0_12LookupResultE.constprop.306
1 0.0% 0.0% _ZN2v88internal20HGlobalValueNumberer12AnalyzeBlockEPNS0_11HBasicBlockEPNS0_9HValueMapE.constprop.605
1 0.0% 0.0% _IO_file_xsputn
1 0.0% 0.0% _IO_default_xsputn
[GC]:
ticks total nonlib name
33 0.0%
[Bottom up (heavy) profile]:
Note: percentage shows a share of a particular caller in the total
amount of its parent calls.
Callers occupying less than 2.0% are not shown.
ticks parent name
81995 99.9% epoll_wait