[CSSPGO] Trim cold base profiles for the CS preinliner.

Adding support to the CS preinliner to trim cold base profiles. This makes trimming consistent with the inline decision made by the preinliner. Also disable the existing profile merger when preinliner is on unless explicitly specified.

Reviewed By: wenlei, wlei

Differential Revision: https://reviews.llvm.org/D112489

diff --git a/llvm/include/llvm/ProfileData/SampleProf.h b/llvm/include/llvm/ProfileData/SampleProf.h
index 89faa83..c61e334 100644 (file)
--- a/llvm/include/llvm/ProfileData/SampleProf.h
+++ b/llvm/include/llvm/ProfileData/SampleProf.h
@@ -1128,11 +1128,18 @@ private:
 class SampleContextTrimmer {
 public:
   SampleContextTrimmer(SampleProfileMap &Profiles) : ProfileMap(Profiles){};
-  // Trim and merge cold context profile when requested.
+  // Trim and merge cold context profile when requested. TrimBaseProfileOnly
+  // should only be effective when TrimColdContext is true. On top of
+  // TrimColdContext, TrimBaseProfileOnly can be used to specify to trim all
+  // cold profiles or only cold base profiles. Trimming base profiles only is
+  // mainly to honor the preinliner decsion. Note that when MergeColdContext is
+  // true, preinliner decsion is not honored anyway so TrimBaseProfileOnly will
+  // be ignored.
   void trimAndMergeColdContextProfiles(uint64_t ColdCountThreshold,
                                        bool TrimColdContext,
                                        bool MergeColdContext,
-                                       uint32_t ColdContextFrameLength);
+                                       uint32_t ColdContextFrameLength,
+                                       bool TrimBaseProfileOnly);
   // Canonicalize context profile name and attributes.
   void canonicalizeContextProfiles();
 

diff --git a/llvm/lib/ProfileData/SampleProf.cpp b/llvm/lib/ProfileData/SampleProf.cpp
index 07af3f2..cb5dd92 100644 (file)
--- a/llvm/lib/ProfileData/SampleProf.cpp
+++ b/llvm/lib/ProfileData/SampleProf.cpp
@@ -331,7 +331,7 @@ std::error_code ProfileSymbolList::read(const uint8_t *Data,
 
 void SampleContextTrimmer::trimAndMergeColdContextProfiles(
     uint64_t ColdCountThreshold, bool TrimColdContext, bool MergeColdContext,
-    uint32_t ColdContextFrameLength) {
+    uint32_t ColdContextFrameLength, bool TrimBaseProfileOnly) {
   if (!TrimColdContext && !MergeColdContext)
     return;
 
@@ -339,14 +339,21 @@ void SampleContextTrimmer::trimAndMergeColdContextProfiles(
   if (ColdCountThreshold == 0)
     return;
 
+  // Trimming base profiles only is mainly to honor the preinliner decsion. When
+  // MergeColdContext is true preinliner decsion is not honored anyway so turn
+  // off TrimBaseProfileOnly.
+  if (MergeColdContext)
+    TrimBaseProfileOnly = false;
+
   // Filter the cold profiles from ProfileMap and move them into a tmp
   // container
   std::vector<std::pair<SampleContext, const FunctionSamples *>> ColdProfiles;
   for (const auto &I : ProfileMap) {
+    const SampleContext &Context = I.first;
     const FunctionSamples &FunctionProfile = I.second;
-    if (FunctionProfile.getTotalSamples() >= ColdCountThreshold)
-      continue;
-    ColdProfiles.emplace_back(I.first, &I.second);
+    if (FunctionProfile.getTotalSamples() < ColdCountThreshold &&
+        (!TrimBaseProfileOnly || Context.isBaseContext()))
+      ColdProfiles.emplace_back(Context, &I.second);
   }
 
   // Remove the cold profile from ProfileMap and merge them into

diff --git a/llvm/test/tools/llvm-profgen/cs-preinline.test b/llvm/test/tools/llvm-profgen/cs-preinline.test
index beca0d0..eda62e8 100644 (file)
--- a/llvm/test/tools/llvm-profgen/cs-preinline.test
+++ b/llvm/test/tools/llvm-profgen/cs-preinline.test
@@ -10,6 +10,11 @@
 ; RUN: llvm-profgen --format=text --perfscript=%S/Inputs/inline-cs-noprobe.perfscript --binary=%S/Inputs/inline-cs-noprobe.perfbin --output=%t --csspgo-preinliner=1  -sample-profile-cold-inline-threshold=0
 ; RUN: FileCheck %s --input-file %t --check-prefix=CHECK-NO-PREINL
 
+; Test cold profile trimming. Only base profiles should be dropped.
+; RUN: llvm-profgen --format=text --perfscript=%S/Inputs/inline-cs-noprobe.perfscript --binary=%S/Inputs/inline-cs-noprobe.perfbin --output=%t --csspgo-preinliner=1  --csprof-trim-cold-context=1 --profile-summary-hot-count=250
+
+; RUN: FileCheck %s --input-file %t --check-prefix=CHECK-TRIM
+
 ; CHECK-DEFAULT:     [main:1 @ foo]:225:0
 ; CHECK-DEFAULT-NEXT: 2.1: 14
 ; CHECK-DEFAULT-NEXT: 3: 15
@@ -39,3 +44,8 @@
 ; CHECK-NO-PREINL-NEXT:[bar]:84:0
 ; CHECK-NO-PREINL-NEXT: 1: 14
 ; CHECK-NO-PREINL-NEXT: !Attributes: 1
+
+; CHECK-TRIM-NOT: [foo]:225:0
+; CHECK-TRIM:[foo:3.1 @ bar]:84:0
+; CHECK-TRIM-NEXT: 1: 14
+; CHECK-TRIM-NEXT: !Attributes: 3

diff --git a/llvm/tools/llvm-profdata/llvm-profdata.cpp b/llvm/tools/llvm-profdata/llvm-profdata.cpp
index 8994b56..fd67cac 100644 (file)
--- a/llvm/tools/llvm-profdata/llvm-profdata.cpp
+++ b/llvm/tools/llvm-profdata/llvm-profdata.cpp
@@ -759,7 +759,7 @@ mergeSampleProfile(const WeightedFileVector &Inputs, SymbolRemapper *Remapper,
     SampleContextTrimmer(ProfileMap)
         .trimAndMergeColdContextProfiles(
             SampleProfColdThreshold, SampleTrimColdContext,
-            SampleMergeColdContext, SampleColdContextFrameDepth);
+            SampleMergeColdContext, SampleColdContextFrameDepth, false);
   }
 
   auto WriterOrErr =

diff --git a/llvm/tools/llvm-profgen/CSPreInliner.cpp b/llvm/tools/llvm-profgen/CSPreInliner.cpp
index 06c3a41..1928da8 100644 (file)
--- a/llvm/tools/llvm-profgen/CSPreInliner.cpp
+++ b/llvm/tools/llvm-profgen/CSPreInliner.cpp
@@ -252,7 +252,7 @@ void CSPreInliner::run() {
   // trim out such profiles from the output.
   std::vector<SampleContext> ProfilesToBeRemoved;
   for (auto &It : ProfileMap) {
-    SampleContext Context = It.second.getContext();
+    SampleContext &Context = It.second.getContext();
     if (!Context.isBaseContext() && !Context.hasState(InlinedContext)) {
       assert(Context.hasState(MergedContext) &&
              "Not inlined context profile should be merged already");

diff --git a/llvm/tools/llvm-profgen/ProfileGenerator.cpp b/llvm/tools/llvm-profgen/ProfileGenerator.cpp
index 6b0a64c..ac8cdec 100644 (file)
--- a/llvm/tools/llvm-profgen/ProfileGenerator.cpp
+++ b/llvm/tools/llvm-profgen/ProfileGenerator.cpp
@@ -657,16 +657,17 @@ void CSProfileGenerator::postProcessProfiles() {
   if (EnableCSPreInliner) {
     CSPreInliner(ProfileMap, *Binary, HotCountThreshold, ColdCountThreshold)
         .run();
+    // Turn off the profile merger by default unless it is explicitly enabled.
+    if (!CSProfMergeColdContext.getNumOccurrences())
+      CSProfMergeColdContext = false;
   }
 
-  // Trim and merge cold context profile using cold threshold above. By default,
-  // we skip such merging and trimming when preinliner is on.
-  if (!EnableCSPreInliner || CSProfTrimColdContext.getNumOccurrences() ||
-      CSProfMergeColdContext.getNumOccurrences()) {
+  // Trim and merge cold context profile using cold threshold above. 
+  if (CSProfTrimColdContext || CSProfMergeColdContext) {
     SampleContextTrimmer(ProfileMap)
         .trimAndMergeColdContextProfiles(
             HotCountThreshold, CSProfTrimColdContext, CSProfMergeColdContext,
-            CSProfMaxColdContextDepth);
+            CSProfMaxColdContextDepth, EnableCSPreInliner);
   }
 }