[llvm] r282833 - [thinlto] Don't decay threshold for hot callsites
Piotr Padlewski via llvm-commits
llvm-commits at lists.llvm.org
Thu Sep 29 20:01:18 PDT 2016
Author: prazek
Date: Thu Sep 29 22:01:17 2016
New Revision: 282833
URL: http://llvm.org/viewvc/llvm-project?rev=282833&view=rev
Log:
[thinlto] Don't decay threshold for hot callsites
Summary:
We don't want to decay hot callsites to import chains of hot
callsites. The same mechanism is used in LIPO.
Reviewers: tejohnson, eraman, mehdi_amini
Subscribers: llvm-commits, mehdi_amini
Differential Revision: https://reviews.llvm.org/D24976
Modified:
llvm/trunk/lib/Transforms/IPO/FunctionImport.cpp
llvm/trunk/test/Transforms/FunctionImport/Inputs/hotness_based_import.ll
llvm/trunk/test/Transforms/FunctionImport/hotness_based_import.ll
Modified: llvm/trunk/lib/Transforms/IPO/FunctionImport.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/FunctionImport.cpp?rev=282833&r1=282832&r2=282833&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/IPO/FunctionImport.cpp (original)
+++ llvm/trunk/lib/Transforms/IPO/FunctionImport.cpp Thu Sep 29 22:01:17 2016
@@ -49,6 +49,13 @@ static cl::opt<float>
"`import-instr-limit` threshold by this factor "
"before processing newly imported functions"));
+static cl::opt<float> ImportHotInstrFactor(
+ "import-hot-evolution-factor", cl::init(1.0), cl::Hidden,
+ cl::value_desc("x"),
+ cl::desc("As we import functions called from hot callsite, multiply the "
+ "`import-instr-limit` threshold by this factor "
+ "before processing newly imported functions"));
+
static cl::opt<float> ImportHotMultiplier(
"import-hot-multiplier", cl::init(3.0), cl::Hidden, cl::value_desc("x"),
cl::desc("Multiply the `import-instr-limit` threshold for hot callsites"));
@@ -300,6 +307,7 @@ static void computeImportForFunction(
const auto NewThreshold =
Threshold * GetBonusMultiplier(Edge.second.Hotness);
+
auto *CalleeSummary = selectCallee(GUID, NewThreshold, Index);
if (!CalleeSummary) {
DEBUG(dbgs() << "ignored! No qualifying callee with summary found.\n");
@@ -348,8 +356,20 @@ static void computeImportForFunction(
}
}
+ auto GetAdjustedThreshold = [](unsigned Threshold, bool IsHotCallsite) {
+ // Adjust the threshold for next level of imported functions.
+ // The threshold is different for hot callsites because we can then
+ // inline chains of hot calls.
+ if (IsHotCallsite)
+ return Threshold * ImportHotInstrFactor;
+ return Threshold * ImportInstrFactor;
+ };
+
+ bool IsHotCallsite = Edge.second.Hotness == CalleeInfo::HotnessType::Hot;
+
// Insert the newly imported function to the worklist.
- Worklist.push_back(std::make_pair(ResolvedCalleeSummary, Threshold));
+ Worklist.emplace_back(ResolvedCalleeSummary,
+ GetAdjustedThreshold(Threshold, IsHotCallsite));
}
}
@@ -380,15 +400,12 @@ static void ComputeImportForModule(
ExportLists);
}
+ // Process the newly imported functions and add callees to the worklist.
while (!Worklist.empty()) {
auto FuncInfo = Worklist.pop_back_val();
auto *Summary = FuncInfo.first;
auto Threshold = FuncInfo.second;
- // Process the newly imported functions and add callees to the worklist.
- // Adjust the threshold
- Threshold = Threshold * ImportInstrFactor;
-
computeImportForFunction(*Summary, Index, Threshold, DefinedGVSummaries,
Worklist, ImportList, ExportLists);
}
Modified: llvm/trunk/test/Transforms/FunctionImport/Inputs/hotness_based_import.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/FunctionImport/Inputs/hotness_based_import.ll?rev=282833&r1=282832&r2=282833&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/FunctionImport/Inputs/hotness_based_import.ll (original)
+++ llvm/trunk/test/Transforms/FunctionImport/Inputs/hotness_based_import.ll Thu Sep 29 22:01:17 2016
@@ -6,38 +6,76 @@ target triple = "x86_64-unknown-linux-gn
define void @hot1() #1 {
ret void
}
-define void @hot2() #1 {
- call void @externalFunction()
- call void @externalFunction()
+define void @hot2() #1 !prof !20 {
+ call void @calledFromHot()
+ call void @calledFromHot()
ret void
}
-define void @hot3() #1 {
- call void @externalFunction()
- call void @externalFunction()
- call void @externalFunction()
+define void @hot3() #1 !prof !20 {
+ call void @calledFromHot()
+ call void @calledFromHot()
+ call void @calledFromHot()
ret void
}
-define void @cold() #1 {
+define void @cold() #1 !prof !0 {
ret void
}
-define void @cold2() #1 {
- call void @externalFunction()
- call void @externalFunction()
+define void @cold2() #1 !prof !0 {
+ call void @calledFromCold()
+ call void @calledFromCold()
ret void
}
define void @none1() #1 {
ret void
}
+
define void @none2() #1 {
- call void @externalFunction()
+ call void @calledFromNone()
ret void
}
define void @none3() #1 {
- call void @externalFunction()
- call void @externalFunction()
+ call void @calledFromNone()
+ call void @calledFromNone()
+ ret void
+}
+
+define void @calledFromCold() {
ret void
}
+define void @calledFromHot() !prof !20 {
+ call void @calledFromHot2()
+ ret void
+}
+
+define void @calledFromHot2() !prof !20 {
+ call void @calledFromHot3()
+ ret void
+}
+
+define void @calledFromNone() !prof !0 {
+ ret void
+}
+
+declare void @calledFromHot3()
+
+!0 = !{!"function_entry_count", i64 1}
+!20 = !{!"function_entry_count", i64 110}
+
+!llvm.module.flags = !{!1}
-declare void @externalFunction()
+!1 = !{i32 1, !"ProfileSummary", !2}
+!2 = !{!3, !4, !5, !6, !7, !8, !9, !10}
+!3 = !{!"ProfileFormat", !"InstrProf"}
+!4 = !{!"TotalCount", i64 10000}
+!5 = !{!"MaxCount", i64 10}
+!6 = !{!"MaxInternalCount", i64 1}
+!7 = !{!"MaxFunctionCount", i64 1000}
+!8 = !{!"NumCounts", i64 3}
+!9 = !{!"NumFunctions", i64 3}
+!10 = !{!"DetailedSummary", !11}
+!11 = !{!12, !13, !14}
+!12 = !{i32 10000, i64 100, i32 1}
+!13 = !{i32 999000, i64 100, i32 1}
+!14 = !{i32 999999, i64 1, i32 2}
\ No newline at end of file
Modified: llvm/trunk/test/Transforms/FunctionImport/hotness_based_import.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/FunctionImport/hotness_based_import.ll?rev=282833&r1=282832&r2=282833&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/FunctionImport/hotness_based_import.ll (original)
+++ llvm/trunk/test/Transforms/FunctionImport/hotness_based_import.ll Thu Sep 29 22:01:17 2016
@@ -3,20 +3,38 @@
; RUN: opt -module-summary %p/Inputs/hotness_based_import.ll -o %t2.bc
; RUN: llvm-lto -thinlto -o %t3 %t.bc %t2.bc
-; Test import with default hot multiplier (3)
+; Test import with default hot multiplier (3) and default hot-evolution-factor (1.0)
; RUN: opt -function-import -summary-file %t3.thinlto.bc %t.bc -import-instr-limit=1 --S | FileCheck %s --check-prefix=CHECK --check-prefix=HOT-DEFAULT
; RUN: opt -function-import -summary-file %t3.thinlto.bc %t.bc -import-instr-limit=1 --S -import-hot-multiplier=3.0 -import-cold-multiplier=0.0 | FileCheck %s --check-prefix=CHECK --check-prefix=HOT-DEFAULT
-
+; RUN: opt -function-import -summary-file %t3.thinlto.bc %t.bc -import-instr-limit=1 --S -import-hot-multiplier=3.0 | FileCheck %s --check-prefix=CHECK --check-prefix=HOT-DEFAULT
+; RUN: opt -function-import -summary-file %t3.thinlto.bc %t.bc -import-instr-limit=1 --S -import-hot-multiplier=3.0 -import-instr-evolution-factor=0.0 | FileCheck %s --check-prefix=CHECK --check-prefix=HOT-DEFAULT
+; RUN: opt -function-import -summary-file %t3.thinlto.bc %t.bc -import-instr-limit=1 --S -import-hot-multiplier=3.0 -import-hot-evolution-factor=1.0 | FileCheck %s --check-prefix=CHECK --check-prefix=HOT-DEFAULT
; HOT-DEFAULT-DAG: define available_externally void @hot1()
; HOT-DEFAULT-DAG: define available_externally void @hot2()
+; HOT-DEFAULT-DAG: define available_externally void @calledFromHot()
+; HOT-DEFAULT-DAG: define available_externally void @calledFromHot2()
; HOT-DEFAULT-DAG: define available_externally void @none1()
-
; HOT-DEFAULT-NOT: define available_externally void @cold()
; HOT-DEFAULT-NOT: define available_externally void @hot3()
; HOT-DEFAULT-NOT: define available_externally void @none2()
; HOT-DEFAULT-NOT: define available_externally void @none3()
; HOT-DEFAULT-NOT: define available_externally void @cold2()
+; HOT-DEFAULT-NOT: define available_externally void @calledFromCold()
+; HOT-DEFAULT-NOT: define available_externally void @calledFromNone()
+; This one tests if we decay threshold for hot callsites. With hot-evolution-factor of 0
+; we should not import any of calledFromHot functions
+; RUN: opt -function-import -summary-file %t3.thinlto.bc %t.bc -import-instr-limit=1 --S -import-hot-multiplier=3.0 -import-hot-evolution-factor=0.0 | FileCheck %s --check-prefix=CHECK --check-prefix=HOT-EVOLUTION
+; HOT-EVOLUTION-DAG: define available_externally void @hot1()
+; HOT-EVOLUTION-DAG: define available_externally void @hot2()
+; HOT-EVOLUTION-DAG: define available_externally void @none1()
+; HOT-EVOLUTION-NOT: define available_externally void @hot3()
+; HOT-EVOLUTION-NOT: define available_externally void @cold()
+; HOT-EVOLUTION-NOT: define available_externally void @none2()
+; HOT-EVOLUTION-NOT: define available_externally void @none3()
+; HOT-EVOLUTION-NOT: define available_externally void @cold2()
+; HOT-EVOLUTION-NOT: define available_externally void @calledFromHot()
+; HOT-EVOLUTION-NOT: define available_externally void @calledFromHot2()
; Test import with hot multiplier 1.0 - treat hot callsites as normal.
; RUN: opt -function-import -summary-file %t3.thinlto.bc %t.bc -import-instr-limit=1 -import-hot-multiplier=1.0 --S | FileCheck %s --check-prefix=CHECK --check-prefix=HOT-ONE
@@ -46,10 +64,13 @@
; HOT-ZERO-DAG: define available_externally void @none2()
; HOT-ZERO-DAG: define available_externally void @none3()
; HOT-ZERO-DAG: define available_externally void @cold2()
+; HOT-ZERO-DAG: define available_externally void @calledFromCold()
+; HOT-ZERO-DAG: define available_externally void @calledFromNone()
; HOT-ZERO-NOT: define available_externally void @hot2()
; HOT-ZERO-NOT: define available_externally void @hot1()
; HOT-ZERO-NOT: define available_externally void @hot3()
-
+; HOT-ZERO-NOT: define available_externally void @calledFromHot()
+; HOT-ZERO-NOT: define available_externally void @calledFromHot2()
; ModuleID = 'thinlto-function-summary-callgraph.ll'
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