JSC should scale the optimization threshold for a code block according to the cost of compiling it
https://bugs.webkit.org/show_bug.cgi?id=104406
Reviewed by Oliver Hunt.
We've long known that we want to scale the execution count threshold needed for the DFG
to kick in to scale according to some estimate of the cost of compiling that code block.
This institutes a relationship like this:
threshold = thresholdSetting * (a * sqrt(instructionCount + b) + abs(c * instructionCount) + d
Where a, b, c, d are coefficients derived from fitting the above expression to various
data points, which I chose based on looking at one benchmark (3d-cube) and from my
own intuitions.
Making this work well also required changing the thresholdForOptimizeAfterLongWarmUp
from 5000 to 1000.
This is a >1% speed-up on SunSpider, a >3% speed-up on V8Spider, ~1% speed-up on V8v7,
neutral on Octane, and neutral on Kraken.
I also out-of-lined a bunch of methods related to these heuristics, because I couldn't
stand having them defined in the header anymore. I also made improvements to debugging
code because I needed it for tuning this change.
* CMakeLists.txt:
* GNUmakefile.list.am:
* JavaScriptCore.vcproj/JavaScriptCore/JavaScriptCore.vcproj:
* JavaScriptCore.xcodeproj/project.pbxproj:
* Target.pri:
* bytecode/CodeBlock.cpp:
(JSC::CodeBlock::sourceCodeForTools):
(JSC::CodeBlock::sourceCodeOnOneLine):
(JSC::CodeBlock::dumpBytecode):
(JSC::CodeBlock::CodeBlock):
(JSC::CodeBlock::reoptimizationRetryCounter):
(JSC::CodeBlock::countReoptimization):
(JSC::CodeBlock::optimizationThresholdScalingFactor):
(JSC::clipThreshold):
(JSC::CodeBlock::counterValueForOptimizeAfterWarmUp):
(JSC::CodeBlock::counterValueForOptimizeAfterLongWarmUp):
(JSC::CodeBlock::counterValueForOptimizeSoon):
(JSC::CodeBlock::checkIfOptimizationThresholdReached):
(JSC::CodeBlock::optimizeNextInvocation):
(JSC::CodeBlock::dontOptimizeAnytimeSoon):
(JSC::CodeBlock::optimizeAfterWarmUp):
(JSC::CodeBlock::optimizeAfterLongWarmUp):
(JSC::CodeBlock::optimizeSoon):
(JSC::CodeBlock::adjustedExitCountThreshold):
(JSC::CodeBlock::exitCountThresholdForReoptimization):
(JSC::CodeBlock::exitCountThresholdForReoptimizationFromLoop):
(JSC::CodeBlock::shouldReoptimizeNow):
(JSC::CodeBlock::shouldReoptimizeFromLoopNow):
* bytecode/CodeBlock.h:
* bytecode/ExecutionCounter.cpp:
(JSC::ExecutionCounter::hasCrossedThreshold):
* bytecode/ReduceWhitespace.cpp: Added.
(JSC::reduceWhitespace):
* bytecode/ReduceWhitespace.h: Added.
* dfg/DFGCapabilities.cpp:
(JSC::DFG::mightCompileEval):
(JSC::DFG::mightCompileProgram):
(JSC::DFG::mightCompileFunctionForCall):
(JSC::DFG::mightCompileFunctionForConstruct):
(JSC::DFG::mightInlineFunctionForCall):
(JSC::DFG::mightInlineFunctionForConstruct):
* dfg/DFGCapabilities.h:
* dfg/DFGDisassembler.cpp:
(JSC::DFG::Disassembler::dumpHeader):
* dfg/DFGOSREntry.cpp:
(JSC::DFG::prepareOSREntry):
* jit/JITDisassembler.cpp:
(JSC::JITDisassembler::dumpHeader):
* jit/JITStubs.cpp:
(JSC::DEFINE_STUB_FUNCTION):
* llint/LLIntSlowPaths.cpp:
(JSC::LLInt::entryOSR):
(JSC::LLInt::LLINT_SLOW_PATH_DECL):
* profiler/ProfilerDatabase.cpp:
(JSC::Profiler::Database::ensureBytecodesFor):
* runtime/Options.h:
git-svn-id: http://svn.webkit.org/repository/webkit/trunk@137094 268f45cc-cd09-0410-ab3c-d52691b4dbfc
diff --git a/Source/JavaScriptCore/bytecode/ExecutionCounter.cpp b/Source/JavaScriptCore/bytecode/ExecutionCounter.cpp
index e619a03..dca9c51 100644
--- a/Source/JavaScriptCore/bytecode/ExecutionCounter.cpp
+++ b/Source/JavaScriptCore/bytecode/ExecutionCounter.cpp
@@ -113,7 +113,8 @@
double modifiedThreshold = applyMemoryUsageHeuristics(m_activeThreshold, codeBlock);
return static_cast<double>(m_totalCount) + m_counter >=
- modifiedThreshold - static_cast<double>(m_activeThreshold) / 2;
+ modifiedThreshold - static_cast<double>(
+ std::min(m_activeThreshold, Options::maximumExecutionCountsBetweenCheckpoints())) / 2;
}
bool ExecutionCounter::setThreshold(CodeBlock* codeBlock)
