Changeset 43047 in webkit for trunk/JavaScriptCore/jsc.cpp

Timestamp:

Apr 30, 2009, 12:52:27 AM (16 years ago)

Author:

[email protected]

Message:

2009-04-30 Gavin Barraclough <​[email protected]>

Reviewed by Maciej Stachowiak.

Add SamplingFlags mechanism.

This mechanism allows fine-grained JSC and JavaScript program aware
performance measurement. The mechanism provides a set of 32 flags,
numbered #1..#32. Flag #16 is initially set, and all other flags
are cleared. Flags may be set and cleared from within

Enable by setting ENABLE_SAMPLING_FLAGS to 1 in wtf/Platform.h.
Disabled by default, no performance impact. Flags may be modified
by calling SamplingFlags::setFlag() and SamplingFlags::clearFlag()
from within JSC implementation, or by calling setSamplingFlag() and
clearSamplingFlag() from JavaScript.

The flags are sampled with a frequency of 10000Hz, and the highest
set flag in recorded, allowing multiple events to be measured (with
the highest flag number representing the highest priority).

Disabled by default; no performance impact.

• JavaScriptCore.exp:
• bytecode/SamplingTool.cpp: (JSC::SamplingFlags::sample): (JSC::SamplingFlags::start): (JSC::SamplingFlags::stop): (JSC::SamplingThread::threadStartFunc): (JSC::SamplingThread::start): (JSC::SamplingThread::stop): (JSC::ScopeSampleRecord::sample): (JSC::SamplingTool::doRun): (JSC::SamplingTool::sample): (JSC::SamplingTool::start): (JSC::SamplingTool::stop):
• bytecode/SamplingTool.h: (JSC::SamplingFlags::setFlag): (JSC::SamplingFlags::clearFlag): (JSC::SamplingTool::SamplingTool):
• jsc.cpp: (GlobalObject::GlobalObject): (functionSetSamplingFlag): (functionClearSamplingFlag): (runWithScripts):
• wtf/Platform.h:

File:

• trunk/JavaScriptCore/jsc.cpp (modified) (6 diffs)

trunk/JavaScriptCore/jsc.cpp

@@ -78 +78 @@
 static NO_RETURN JSValuePtr functionQuit(ExecState*, JSObject*, JSValuePtr, const ArgList&);
 
+#if ENABLE(SAMPLING_FLAGS)
+static JSValuePtr functionSetSamplingFlag(ExecState*, JSObject*, JSValuePtr, const ArgList&);
+static JSValuePtr functionClearSamplingFlag(ExecState*, JSObject*, JSValuePtr, const ArgList&);
+#endif
+
 struct Script {
     bool isFile;
@@ -181 +186 @@
     putDirectFunction(globalExec(), new (globalExec()) PrototypeFunction(globalExec(), prototypeFunctionStructure(), 0, Identifier(globalExec(), "readline"), functionReadline));
 
+#if ENABLE(SAMPLING_FLAGS)
+    putDirectFunction(globalExec(), new (globalExec()) PrototypeFunction(globalExec(), prototypeFunctionStructure(), 1, Identifier(globalExec(), "setSamplingFlag"), functionSetSamplingFlag));
+    putDirectFunction(globalExec(), new (globalExec()) PrototypeFunction(globalExec(), prototypeFunctionStructure(), 1, Identifier(globalExec(), "clearSamplingFlag"), functionClearSamplingFlag));
+#endif
+
     JSObject* array = constructEmptyArray(globalExec());
     for (size_t i = 0; i < arguments.size(); ++i)
@@ -251 +261 @@
     return result.value();
 }
+
+#if ENABLE(SAMPLING_FLAGS)
+JSValuePtr functionSetSamplingFlag(ExecState* exec, JSObject*, JSValuePtr, const ArgList& args)
+{
+    unsigned flag = static_cast<unsigned>(args.at(0).toNumber(exec));
+
+    // Sanitize the input into the range 1..32.
+    if (flag > 32)
+        flag &= 31;
+    if (!flag)
+        flag = 32;
+
+    SamplingFlags::setFlag(flag);
+
+    return jsNull();
+}
+
+JSValuePtr functionClearSamplingFlag(ExecState* exec, JSObject*, JSValuePtr, const ArgList& args)
+{
+    unsigned flag = static_cast<unsigned>(args.at(0).toNumber(exec));
+
+    // Sanitize the input into the range 1..32.
+    if (flag > 32)
+        flag &= 31;
+    if (!flag)
+        flag = 32;
+
+    SamplingFlags::clearFlag(flag);
+
+    return jsNull();
+}
+#endif
 
 JSValuePtr functionReadline(ExecState* exec, JSObject*, JSValuePtr, const ArgList&)
@@ -340 +382 @@
     Interpreter* interpreter = globalObject->globalData()->interpreter;
     interpreter->setSampler(new SamplingTool(interpreter));
+    interpreter->sampler()->setup();
+#endif
+#if ENABLE(SAMPLING_FLAGS)
+    SamplingFlags::start();
 #endif
 
@@ -354 +400 @@
         }
 
-#if ENABLE(OPCODE_SAMPLING)
-        interpreter->sampler()->start();
-#endif
+#if ENABLE(SAMPLING_THREAD)
+        SamplingThread::start();
+#endif
+
         Completion completion = evaluate(globalObject->globalExec(), globalObject->globalScopeChain(), makeSource(script, fileName));
         success = success && completion.complType() != Throw;
@@ -366 +413 @@
         }
 
+#if ENABLE(SAMPLING_THREAD)
+        SamplingThread::stop();
+#endif
+
         globalObject->globalExec()->clearException();
-
-#if ENABLE(OPCODE_SAMPLING)
-        interpreter->sampler()->stop();
-#endif
-    }
-
+    }
+
+#if ENABLE(SAMPLING_FLAGS)
+    SamplingFlags::stop();
+#endif
 #if ENABLE(OPCODE_SAMPLING)
     interpreter->sampler()->dump(globalObject->globalExec());