From ba72b95f7bf2e3ea7fc49fa282c694ecf9f4fb62 Mon Sep 17 00:00:00 2001 From: Piotr Padlewski Date: Thu, 29 Sep 2016 17:32:07 +0000 Subject: [thinlto] Add cold-callsite import heuristic Summary: Not tunned up heuristic, but with this small heuristic there is about +0.10% improvement on SPEC 2006 Reviewers: tejohnson, mehdi_amini, eraman Subscribers: mehdi_amini, llvm-commits Differential Revision: https://reviews.llvm.org/D24940 llvm-svn: 282733 --- llvm/lib/Transforms/IPO/FunctionImport.cpp | 22 ++++++++++++++++------ 1 file changed, 16 insertions(+), 6 deletions(-) (limited to 'llvm/lib/Transforms/IPO/FunctionImport.cpp') diff --git a/llvm/lib/Transforms/IPO/FunctionImport.cpp b/llvm/lib/Transforms/IPO/FunctionImport.cpp index 6c43b780870..58877b1dc05 100644 --- a/llvm/lib/Transforms/IPO/FunctionImport.cpp +++ b/llvm/lib/Transforms/IPO/FunctionImport.cpp @@ -48,10 +48,15 @@ static cl::opt cl::desc("As we import functions, multiply the " "`import-instr-limit` threshold by this factor " "before processing newly imported functions")); + static cl::opt ImportHotMultiplier( "import-hot-multiplier", cl::init(3.0), cl::Hidden, cl::value_desc("x"), - cl::ZeroOrMore, cl::desc("Multiply the `import-instr-limit` threshold for " - "hot callsites")); + cl::desc("Multiply the `import-instr-limit` threshold for hot callsites")); + +// FIXME: This multiplier was not really tuned up. +static cl::opt ImportColdMultiplier( + "import-cold-multiplier", cl::init(0), cl::Hidden, cl::value_desc("N"), + cl::desc("Multiply the `import-instr-limit` threshold for cold callsites")); static cl::opt PrintImports("print-imports", cl::init(false), cl::Hidden, cl::desc("Print imported functions")); @@ -285,11 +290,16 @@ static void computeImportForFunction( continue; } - // FIXME: Also lower the threshold for cold callsites. + auto GetBonusMultiplier = [](CalleeInfo::HotnessType Hotness) -> float { + if (Hotness == CalleeInfo::HotnessType::Hot) + return ImportHotMultiplier; + if (Hotness == CalleeInfo::HotnessType::Cold) + return ImportColdMultiplier; + return 1.0; + }; + const auto NewThreshold = - Edge.second.Hotness == CalleeInfo::HotnessType::Hot - ? Threshold * ImportHotMultiplier - : Threshold; + Threshold * GetBonusMultiplier(Edge.second.Hotness); auto *CalleeSummary = selectCallee(GUID, NewThreshold, Index); if (!CalleeSummary) { DEBUG(dbgs() << "ignored! No qualifying callee with summary found.\n"); -- cgit v1.2.3