diff options
Diffstat (limited to 'bolt/lib/Profile/StaleProfileMatching.cpp')
| -rw-r--r-- | bolt/lib/Profile/StaleProfileMatching.cpp | 30 |
1 files changed, 23 insertions, 7 deletions
diff --git a/bolt/lib/Profile/StaleProfileMatching.cpp b/bolt/lib/Profile/StaleProfileMatching.cpp index 365bc53..c9bcd04 100644 --- a/bolt/lib/Profile/StaleProfileMatching.cpp +++ b/bolt/lib/Profile/StaleProfileMatching.cpp @@ -51,6 +51,12 @@ cl::opt<bool> cl::desc("Infer counts from stale profile data."), cl::init(false), cl::Hidden, cl::cat(BoltOptCategory)); +cl::opt<unsigned> StaleMatchingMinMatchedBlock( + "stale-matching-min-matched-block", + cl::desc("Percentage threshold of matched basic blocks at which stale " + "profile inference is executed."), + cl::init(0), cl::Hidden, cl::cat(BoltOptCategory)); + cl::opt<unsigned> StaleMatchingMaxFuncSize( "stale-matching-max-func-size", cl::desc("The maximum size of a function to consider for inference."), @@ -391,10 +397,9 @@ createFlowFunction(const BinaryFunction::BasicBlockOrderType &BlockOrder) { /// of the basic blocks in the binary, the count is "matched" to the block. /// Similarly, if both the source and the target of a count in the profile are /// matched to a jump in the binary, the count is recorded in CFG. -void matchWeightsByHashes(BinaryContext &BC, - const BinaryFunction::BasicBlockOrderType &BlockOrder, - const yaml::bolt::BinaryFunctionProfile &YamlBF, - FlowFunction &Func) { +size_t matchWeightsByHashes( + BinaryContext &BC, const BinaryFunction::BasicBlockOrderType &BlockOrder, + const yaml::bolt::BinaryFunctionProfile &YamlBF, FlowFunction &Func) { assert(Func.Blocks.size() == BlockOrder.size() + 1); std::vector<FlowBlock *> Blocks; @@ -500,6 +505,8 @@ void matchWeightsByHashes(BinaryContext &BC, Block.HasUnknownWeight = false; Block.Weight = std::max(OutWeight[Block.Index], InWeight[Block.Index]); } + + return MatchedBlocks.size(); } /// The function finds all blocks that are (i) reachable from the Entry block @@ -575,10 +582,16 @@ void preprocessUnreachableBlocks(FlowFunction &Func) { /// Decide if stale profile matching can be applied for a given function. /// Currently we skip inference for (very) large instances and for instances /// having "unexpected" control flow (e.g., having no sink basic blocks). -bool canApplyInference(const FlowFunction &Func) { +bool canApplyInference(const FlowFunction &Func, + const yaml::bolt::BinaryFunctionProfile &YamlBF, + const uint64_t &MatchedBlocks) { if (Func.Blocks.size() > opts::StaleMatchingMaxFuncSize) return false; + if (MatchedBlocks * 100 < + opts::StaleMatchingMinMatchedBlock * YamlBF.Blocks.size()) + return false; + bool HasExitBlocks = llvm::any_of( Func.Blocks, [&](const FlowBlock &Block) { return Block.isExit(); }); if (!HasExitBlocks) @@ -725,18 +738,21 @@ bool YAMLProfileReader::inferStaleProfile( const BinaryFunction::BasicBlockOrderType BlockOrder( BF.getLayout().block_begin(), BF.getLayout().block_end()); + // Tracks the number of matched blocks. + // Create a wrapper flow function to use with the profile inference algorithm. FlowFunction Func = createFlowFunction(BlockOrder); // Match as many block/jump counts from the stale profile as possible - matchWeightsByHashes(BF.getBinaryContext(), BlockOrder, YamlBF, Func); + size_t MatchedBlocks = + matchWeightsByHashes(BF.getBinaryContext(), BlockOrder, YamlBF, Func); // Adjust the flow function by marking unreachable blocks Unlikely so that // they don't get any counts assigned. preprocessUnreachableBlocks(Func); // Check if profile inference can be applied for the instance. - if (!canApplyInference(Func)) + if (!canApplyInference(Func, YamlBF, MatchedBlocks)) return false; // Apply the profile inference algorithm. |