llvm::sampleprof::DefaultFunctionPruningStrategy Class Reference

#include "llvm/ProfileData/SampleProfWriter.h"

Inheritance diagram for llvm::sampleprof::DefaultFunctionPruningStrategy:

Public Member Functions
	DefaultFunctionPruningStrategy (SampleProfileMap &ProfileMap, size_t OutputSizeLimit)
void	Erase (size_t CurrentOutputSize) override
	In this default implementation, functions with fewest samples are dropped first.
Public Member Functions inherited from llvm::sampleprof::FunctionPruningStrategy
	FunctionPruningStrategy (SampleProfileMap &ProfileMap, size_t OutputSizeLimit)
	ProfileMap A reference to the original profile map.
virtual	~FunctionPruningStrategy ()=default
virtual void	Erase (size_t CurrentOutputSize)=0
	SampleProfileWriter::writeWithSizeLimit() calls this after every write iteration if the output size still exceeds the limit.

Additional Inherited Members
Protected Attributes inherited from llvm::sampleprof::FunctionPruningStrategy
SampleProfileMap &	ProfileMap
size_t	OutputSizeLimit

Detailed Description

Definition at line 68 of file SampleProfWriter.h.

Constructor & Destructor Documentation

DefaultFunctionPruningStrategy()

DefaultFunctionPruningStrategy::DefaultFunctionPruningStrategy	(	SampleProfileMap &	ProfileMap,
		size_t	OutputSizeLimit
	)

Definition at line 70 of file SampleProfWriter.cpp.

References llvm::sampleprof::FunctionPruningStrategy::ProfileMap, and llvm::sampleprof::sortFuncProfiles().

Member Function Documentation

Erase()

void DefaultFunctionPruningStrategy::Erase ( size_t  CurrentOutputSize )

overridevirtual

In this default implementation, functions with fewest samples are dropped first.

Since the exact size of the output cannot be easily calculated due to compression, we use a heuristic to remove as many functions as necessary but not too many, aiming to minimize the number of write iterations. Empirically, functions with larger total sample count contain linearly more sample entries, meaning it takes linearly more space to write them. The cumulative length is therefore quadratic if all functions are sorted by total sample count. TODO: Find better heuristic.

Implements llvm::sampleprof::FunctionPruningStrategy.

Definition at line 76 of file SampleProfWriter.cpp.

References assert(), D, llvm::drop_begin(), llvm::sampleprof::SampleProfileMap::erase(), llvm::sampleprof::FunctionPruningStrategy::OutputSizeLimit, llvm::sampleprof::FunctionPruningStrategy::ProfileMap, and round().

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The documentation for this class was generated from the following files:

• include/llvm/ProfileData/SampleProfWriter.h
• lib/ProfileData/SampleProfWriter.cpp