[llvm] r310005 - Use profile summary to disable peeling for huge working sets
Teresa Johnson via llvm-commits
llvm-commits at lists.llvm.org
Thu Aug 3 16:42:58 PDT 2017
Author: tejohnson
Date: Thu Aug 3 16:42:58 2017
New Revision: 310005
URL: http://llvm.org/viewvc/llvm-project?rev=310005&view=rev
Log:
Use profile summary to disable peeling for huge working sets
Summary:
Detect when the working set size of a profiled application is huge,
by comparing the number of counts required to reach the hot percentile
in the profile summary to a large threshold*.
When the working set size is determined to be huge, disable peeling
to avoid bloating the working set further.
*Note that the selected threshold (15K) is significantly larger than the
largest working set value in SPEC cpu2006 (which is gcc at around 11K).
Reviewers: davidxl
Subscribers: mehdi_amini, mzolotukhin, eraman, llvm-commits
Differential Revision: https://reviews.llvm.org/D36288
Modified:
llvm/trunk/include/llvm/Analysis/ProfileSummaryInfo.h
llvm/trunk/lib/Analysis/ProfileSummaryInfo.cpp
llvm/trunk/lib/Transforms/Scalar/LoopUnrollPass.cpp
llvm/trunk/test/Other/new-pm-defaults.ll
llvm/trunk/test/Other/new-pm-thinlto-defaults.ll
llvm/trunk/test/Transforms/LoopUnroll/peel-loop-pgo.ll
Modified: llvm/trunk/include/llvm/Analysis/ProfileSummaryInfo.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/ProfileSummaryInfo.h?rev=310005&r1=310004&r2=310005&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Analysis/ProfileSummaryInfo.h (original)
+++ llvm/trunk/include/llvm/Analysis/ProfileSummaryInfo.h Thu Aug 3 16:42:58 2017
@@ -49,6 +49,10 @@ private:
void computeThresholds();
// Count thresholds to answer isHotCount and isColdCount queries.
Optional<uint64_t> HotCountThreshold, ColdCountThreshold;
+ // True if the working set size of the code is considered huge,
+ // because the number of profile counts required to reach the hot
+ // percentile is above a huge threshold.
+ Optional<bool> HasHugeWorkingSetSize;
public:
ProfileSummaryInfo(Module &M) : M(M) {}
@@ -84,6 +88,8 @@ public:
/// Returns the profile count for \p CallInst.
Optional<uint64_t> getProfileCount(const Instruction *CallInst,
BlockFrequencyInfo *BFI);
+ /// Returns true if the working set size of the code is considered huge.
+ bool hasHugeWorkingSetSize();
/// \brief Returns true if \p F has hot function entry.
bool isFunctionEntryHot(const Function *F);
/// Returns true if \p F has hot function entry or hot call edge.
Modified: llvm/trunk/lib/Analysis/ProfileSummaryInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ProfileSummaryInfo.cpp?rev=310005&r1=310004&r2=310005&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/ProfileSummaryInfo.cpp (original)
+++ llvm/trunk/lib/Analysis/ProfileSummaryInfo.cpp Thu Aug 3 16:42:58 2017
@@ -44,10 +44,16 @@ static cl::opt<bool> AccurateSampleProfi
cl::desc("If the sample profile is accurate, we will mark all un-sampled "
"callsite as cold. Otherwise, treat un-sampled callsites as if "
"we have no profile."));
-
-// Find the minimum count to reach a desired percentile of counts.
-static uint64_t getMinCountForPercentile(SummaryEntryVector &DS,
- uint64_t Percentile) {
+static cl::opt<unsigned> ProfileSummaryHugeWorkingSetSizeThreshold(
+ "profile-summary-huge-working-set-size-threshold", cl::Hidden,
+ cl::init(15000), cl::ZeroOrMore,
+ cl::desc("The code working set size is considered huge if the number of"
+ " blocks required to reach the -profile-summary-cutoff-hot"
+ " percentile exceeds this count."));
+
+// Find the summary entry for a desired percentile of counts.
+static const ProfileSummaryEntry &getEntryForPercentile(SummaryEntryVector &DS,
+ uint64_t Percentile) {
auto Compare = [](const ProfileSummaryEntry &Entry, uint64_t Percentile) {
return Entry.Cutoff < Percentile;
};
@@ -56,7 +62,7 @@ static uint64_t getMinCountForPercentile
// detailed summary.
if (It == DS.end())
report_fatal_error("Desired percentile exceeds the maximum cutoff");
- return It->MinCount;
+ return *It;
}
// The profile summary metadata may be attached either by the frontend or by
@@ -169,10 +175,20 @@ void ProfileSummaryInfo::computeThreshol
if (!computeSummary())
return;
auto &DetailedSummary = Summary->getDetailedSummary();
- HotCountThreshold =
- getMinCountForPercentile(DetailedSummary, ProfileSummaryCutoffHot);
- ColdCountThreshold =
- getMinCountForPercentile(DetailedSummary, ProfileSummaryCutoffCold);
+ auto &HotEntry =
+ getEntryForPercentile(DetailedSummary, ProfileSummaryCutoffHot);
+ HotCountThreshold = HotEntry.MinCount;
+ auto &ColdEntry =
+ getEntryForPercentile(DetailedSummary, ProfileSummaryCutoffCold);
+ ColdCountThreshold = ColdEntry.MinCount;
+ HasHugeWorkingSetSize =
+ HotEntry.NumCounts > ProfileSummaryHugeWorkingSetSizeThreshold;
+}
+
+bool ProfileSummaryInfo::hasHugeWorkingSetSize() {
+ if (!HasHugeWorkingSetSize)
+ computeThresholds();
+ return HasHugeWorkingSetSize && HasHugeWorkingSetSize.getValue();
}
bool ProfileSummaryInfo::isHotCount(uint64_t C) {
Modified: llvm/trunk/lib/Transforms/Scalar/LoopUnrollPass.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/LoopUnrollPass.cpp?rev=310005&r1=310004&r2=310005&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/LoopUnrollPass.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/LoopUnrollPass.cpp Thu Aug 3 16:42:58 2017
@@ -21,6 +21,7 @@
#include "llvm/Analysis/LoopPass.h"
#include "llvm/Analysis/LoopUnrollAnalyzer.h"
#include "llvm/Analysis/OptimizationDiagnosticInfo.h"
+#include "llvm/Analysis/ProfileSummaryInfo.h"
#include "llvm/Analysis/ScalarEvolution.h"
#include "llvm/Analysis/ScalarEvolutionExpressions.h"
#include "llvm/IR/DataLayout.h"
@@ -1252,6 +1253,11 @@ PreservedAnalyses LoopUnrollPass::run(Fu
auto &AC = AM.getResult<AssumptionAnalysis>(F);
auto &ORE = AM.getResult<OptimizationRemarkEmitterAnalysis>(F);
+ const ModuleAnalysisManager &MAM =
+ AM.getResult<ModuleAnalysisManagerFunctionProxy>(F).getManager();
+ ProfileSummaryInfo *PSI =
+ MAM.getCachedResult<ProfileSummaryAnalysis>(*F.getParent());
+
bool Changed = false;
// The unroller requires loops to be in simplified form, and also needs LCSSA.
@@ -1280,12 +1286,18 @@ PreservedAnalyses LoopUnrollPass::run(Fu
// states we support: partial and full (or "simple") unrolling. However, to
// enable these things we actually pass "None" in for the optional to avoid
// providing an explicit choice.
- Optional<bool> AllowPartialParam, RuntimeParam, UpperBoundParam;
- bool CurChanged = tryToUnrollLoop(
- &L, DT, &LI, SE, TTI, AC, ORE,
- /*PreserveLCSSA*/ true, OptLevel, /*Count*/ None,
- /*Threshold*/ None, AllowPartialParam, RuntimeParam, UpperBoundParam,
- /*AllowPeeling*/ None);
+ Optional<bool> AllowPartialParam, RuntimeParam, UpperBoundParam,
+ AllowPeeling;
+ // Check if the profile summary indicates that the profiled application
+ // has a huge working set size, in which case we disable peeling to avoid
+ // bloating it further.
+ if (PSI && PSI->hasHugeWorkingSetSize())
+ AllowPeeling = false;
+ bool CurChanged =
+ tryToUnrollLoop(&L, DT, &LI, SE, TTI, AC, ORE,
+ /*PreserveLCSSA*/ true, OptLevel, /*Count*/ None,
+ /*Threshold*/ None, AllowPartialParam, RuntimeParam,
+ UpperBoundParam, AllowPeeling);
Changed |= CurChanged;
// The parent must not be damaged by unrolling!
Modified: llvm/trunk/test/Other/new-pm-defaults.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Other/new-pm-defaults.ll?rev=310005&r1=310004&r2=310005&view=diff
==============================================================================
--- llvm/trunk/test/Other/new-pm-defaults.ll (original)
+++ llvm/trunk/test/Other/new-pm-defaults.ll Thu Aug 3 16:42:58 2017
@@ -198,6 +198,7 @@
; CHECK-O-NEXT: Running pass: SimplifyCFGPass
; CHECK-O-NEXT: Running pass: InstCombinePass
; CHECK-O-NEXT: Running pass: LoopUnrollPass
+; CHECK-O-NEXT: Running analysis: OuterAnalysisManagerProxy
; CHECK-O-NEXT: Running pass: InstCombinePass
; CHECK-O-NEXT: Running pass: RequireAnalysisPass<{{.*}}OptimizationRemarkEmitterAnalysis
; CHECK-O-NEXT: Running pass: FunctionToLoopPassAdaptor<{{.*}}LICMPass
Modified: llvm/trunk/test/Other/new-pm-thinlto-defaults.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Other/new-pm-thinlto-defaults.ll?rev=310005&r1=310004&r2=310005&view=diff
==============================================================================
--- llvm/trunk/test/Other/new-pm-thinlto-defaults.ll (original)
+++ llvm/trunk/test/Other/new-pm-thinlto-defaults.ll Thu Aug 3 16:42:58 2017
@@ -185,6 +185,7 @@
; CHECK-POSTLINK-O-NEXT: Running pass: SimplifyCFGPass
; CHECK-POSTLINK-O-NEXT: Running pass: InstCombinePass
; CHECK-POSTLINK-O-NEXT: Running pass: LoopUnrollPass
+; CHECK-POSTLINK-O-NEXT: Running analysis: OuterAnalysisManagerProxy
; CHECK-POSTLINK-O-NEXT: Running pass: InstCombinePass
; CHECK-POSTLINK-O-NEXT: Running pass: RequireAnalysisPass<{{.*}}OptimizationRemarkEmitterAnalysis
; CHECK-POSTLINK-O-NEXT: Running pass: FunctionToLoopPassAdaptor<{{.*}}LICMPass
Modified: llvm/trunk/test/Transforms/LoopUnroll/peel-loop-pgo.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopUnroll/peel-loop-pgo.ll?rev=310005&r1=310004&r2=310005&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/LoopUnroll/peel-loop-pgo.ll (original)
+++ llvm/trunk/test/Transforms/LoopUnroll/peel-loop-pgo.ll Thu Aug 3 16:42:58 2017
@@ -1,5 +1,8 @@
; RUN: opt < %s -S -debug-only=loop-unroll -loop-unroll 2>&1 | FileCheck %s
-; RUN: opt < %s -S -debug-only=loop-unroll -passes='require<opt-remark-emit>,unroll' 2>&1 | FileCheck %s
+; RUN: opt < %s -S -debug-only=loop-unroll -passes='require<profile-summary>,function(require<opt-remark-emit>,unroll)' 2>&1 | FileCheck %s
+; Confirm that peeling is disabled if the number of counts required to reach
+; the hot percentile is above the threshold.
+; RUN: opt < %s -S -profile-summary-huge-working-set-size-threshold=9 -debug-only=loop-unroll -passes='require<profile-summary>,function(require<opt-remark-emit>,unroll)' 2>&1 | FileCheck %s --check-prefix=NOPEEL
; REQUIRES: asserts
; Make sure we use the profile information correctly to peel-off 3 iterations
@@ -11,19 +14,19 @@
; CHECK-NOT: PEELING
; Confirm that no peeling occurs when we are performing full unrolling.
-; RUN: opt < %s -S -debug-only=loop-unroll -passes='require<opt-remark-emit>,loop(unroll-full)' 2>&1 | FileCheck %s --check-prefix=FULLUNROLL
-; FULLUNROLL-NOT: PEELING
+; RUN: opt < %s -S -debug-only=loop-unroll -passes='require<opt-remark-emit>,loop(unroll-full)' 2>&1 | FileCheck %s --check-prefix=NOPEEL
+; NOPEEL-NOT: PEELING
; CHECK-LABEL: @basic
-; CHECK: br i1 %{{.*}}, label %[[NEXT0:.*]], label %for.cond.for.end_crit_edge, !prof !1
+; CHECK: br i1 %{{.*}}, label %[[NEXT0:.*]], label %for.cond.for.end_crit_edge, !prof !15
; CHECK: [[NEXT0]]:
-; CHECK: br i1 %{{.*}}, label %[[NEXT1:.*]], label %for.cond.for.end_crit_edge, !prof !2
+; CHECK: br i1 %{{.*}}, label %[[NEXT1:.*]], label %for.cond.for.end_crit_edge, !prof !16
; CHECK: [[NEXT1]]:
-; CHECK: br i1 %{{.*}}, label %[[NEXT2:.*]], label %for.cond.for.end_crit_edge, !prof !3
+; CHECK: br i1 %{{.*}}, label %[[NEXT2:.*]], label %for.cond.for.end_crit_edge, !prof !17
; CHECK: [[NEXT2]]:
-; CHECK: br i1 %{{.*}}, label %for.body, label %{{.*}}, !prof !4
+; CHECK: br i1 %{{.*}}, label %for.body, label %{{.*}}, !prof !18
-define void @basic(i32* %p, i32 %k) #0 !prof !0 {
+define void @basic(i32* %p, i32 %k) #0 !prof !15 {
entry:
%cmp3 = icmp slt i32 0, %k
br i1 %cmp3, label %for.body.lr.ph, label %for.end
@@ -38,7 +41,7 @@ for.body:
store i32 %i.05, i32* %p.addr.04, align 4
%inc = add nsw i32 %i.05, 1
%cmp = icmp slt i32 %inc, %k
- br i1 %cmp, label %for.body, label %for.cond.for.end_crit_edge, !prof !1
+ br i1 %cmp, label %for.body, label %for.cond.for.end_crit_edge, !prof !16
for.cond.for.end_crit_edge: ; preds = %for.body
br label %for.end
@@ -54,7 +57,7 @@ for.end:
; CHECK: for.body:
; CHECK-NOT: br
; CHECK: br i1 %cmp, label %for.body, label %for.cond.for.end_crit_edge
-define void @optsize(i32* %p, i32 %k) #1 !prof !0 {
+define void @optsize(i32* %p, i32 %k) #1 !prof !15 {
entry:
%cmp3 = icmp slt i32 0, %k
br i1 %cmp3, label %for.body.lr.ph, label %for.end
@@ -69,7 +72,7 @@ for.body:
store i32 %i.05, i32* %p.addr.04, align 4
%inc = add nsw i32 %i.05, 1
%cmp = icmp slt i32 %inc, %k
- br i1 %cmp, label %for.body, label %for.cond.for.end_crit_edge, !prof !1
+ br i1 %cmp, label %for.body, label %for.cond.for.end_crit_edge, !prof !16
for.cond.for.end_crit_edge: ; preds = %for.body
br label %for.end
@@ -81,11 +84,27 @@ for.end:
attributes #0 = { nounwind }
attributes #1 = { nounwind optsize }
-!0 = !{!"function_entry_count", i64 1}
-!1 = !{!"branch_weights", i32 3001, i32 1001}
+!llvm.module.flags = !{!1}
-;CHECK: !1 = !{!"branch_weights", i32 900, i32 101}
-;CHECK: !2 = !{!"branch_weights", i32 540, i32 360}
-;CHECK: !3 = !{!"branch_weights", i32 162, i32 378}
-;CHECK: !4 = !{!"branch_weights", i32 1399, i32 162}
+!1 = !{i32 1, !"ProfileSummary", !2}
+!2 = !{!3, !4, !5, !6, !7, !8, !9, !10}
+!3 = !{!"ProfileFormat", !"InstrProf"}
+!4 = !{!"TotalCount", i64 10}
+!5 = !{!"MaxCount", i64 3}
+!6 = !{!"MaxInternalCount", i64 1}
+!7 = !{!"MaxFunctionCount", i64 3}
+!8 = !{!"NumCounts", i64 2}
+!9 = !{!"NumFunctions", i64 2}
+!10 = !{!"DetailedSummary", !11}
+!11 = !{!12, !13, !14}
+!12 = !{i32 10000, i64 3, i32 2}
+!13 = !{i32 999000, i64 1, i32 10}
+!14 = !{i32 999999, i64 1, i32 10}
+!15 = !{!"function_entry_count", i64 1}
+!16 = !{!"branch_weights", i32 3001, i32 1001}
+
+;CHECK: !15 = !{!"branch_weights", i32 900, i32 101}
+;CHECK: !16 = !{!"branch_weights", i32 540, i32 360}
+;CHECK: !17 = !{!"branch_weights", i32 162, i32 378}
+;CHECK: !18 = !{!"branch_weights", i32 1399, i32 162}
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