Rework and simplify initial versioning and tiering rules

src/coreclr/vm/callcounting.cpp

@@ -25,30 +25,6 @@ const PCODE CallCountingStub::TargetForThresholdReached = (PCODE)GetEEFuncEntryP
 
 #ifndef DACCESS_COMPILE
 
-CallCountingManager::CallCountingInfo::CallCountingInfo(NativeCodeVersion codeVersion)
-    : m_codeVersion(codeVersion),
-    m_callCountingStub(nullptr),
-    m_remainingCallCount(0),
-    m_stage(Stage::Disabled)
-{
-    WRAPPER_NO_CONTRACT;
-    _ASSERTE(!codeVersion.IsNull());
-}
-
-CallCountingManager::CallCountingInfo *
-CallCountingManager::CallCountingInfo::CreateWithCallCountingDisabled(NativeCodeVersion codeVersion)
-{
-    CONTRACTL
-    {
-        THROWS;
-        GC_NOTRIGGER;
-        MODE_ANY;
-    }
-    CONTRACTL_END;
-
-    return new CallCountingInfo(codeVersion);
-}
-
 CallCountingManager::CallCountingInfo::CallCountingInfo(NativeCodeVersion codeVersion, CallCount callCountThreshold)
     : m_codeVersion(codeVersion),
     m_callCountingStub(nullptr),
@@ -88,7 +64,6 @@ NativeCodeVersion CallCountingManager::CallCountingInfo::GetCodeVersion() const
 const CallCountingStub *CallCountingManager::CallCountingInfo::GetCallCountingStub() const
 {
     WRAPPER_NO_CONTRACT;
-    _ASSERTE(m_stage != Stage::Disabled);
 
     return m_callCountingStub;
 }
@@ -118,7 +93,6 @@ void CallCountingManager::CallCountingInfo::ClearCallCountingStub()
 PTR_CallCount CallCountingManager::CallCountingInfo::GetRemainingCallCountCell()
 {
     WRAPPER_NO_CONTRACT;
-    _ASSERTE(m_stage != Stage::Disabled);
     //_ASSERTE(m_callCountingStub != nullptr);
 
     return &m_remainingCallCount;
@@ -136,7 +110,6 @@ CallCountingManager::CallCountingInfo::Stage CallCountingManager::CallCountingIn
 FORCEINLINE void CallCountingManager::CallCountingInfo::SetStage(Stage stage)
 {
     WRAPPER_NO_CONTRACT;
-    _ASSERTE(m_stage != Stage::Disabled);
     _ASSERTE(stage <= Stage::Complete);
 
     switch (stage)
@@ -482,59 +455,8 @@ void CallCountingManager::StaticInitialize()
 }
 #endif
 
-bool CallCountingManager::IsCallCountingEnabled(NativeCodeVersion codeVersion)
-{
-    CONTRACTL
-    {
-        NOTHROW;
-        GC_NOTRIGGER;
-        MODE_ANY;
-    }
-    CONTRACTL_END;
-
-    _ASSERTE(!codeVersion.IsNull());
-    _ASSERTE(codeVersion.IsDefaultVersion());
-    _ASSERTE(codeVersion.GetMethodDesc()->IsEligibleForTieredCompilation());
-
-    CodeVersionManager::LockHolder codeVersioningLockHolder;
-
-    PTR_CallCountingInfo callCountingInfo = m_callCountingInfoByCodeVersionHash.Lookup(codeVersion);
-    return callCountingInfo == NULL || callCountingInfo->GetStage() != CallCountingInfo::Stage::Disabled;
-}
-
 #ifndef DACCESS_COMPILE
 
-void CallCountingManager::DisableCallCounting(NativeCodeVersion codeVersion)
-{
-    CONTRACTL
-    {
-        THROWS;
-        GC_NOTRIGGER;
-        MODE_ANY;
-    }
-    CONTRACTL_END;
-
-    _ASSERTE(!codeVersion.IsNull());
-    _ASSERTE(codeVersion.IsDefaultVersion());
-    _ASSERTE(codeVersion.GetMethodDesc()->IsEligibleForTieredCompilation());
-
-    CodeVersionManager::LockHolder codeVersioningLockHolder;
-
-    CallCountingInfo *callCountingInfo = m_callCountingInfoByCodeVersionHash.Lookup(codeVersion);
-    if (callCountingInfo != nullptr)
-    {
-        // Call counting may already have been disabled due to the possibility of concurrent or reentering JIT of the same
-        // native code version of a method. The call counting info is created with call counting enabled or disabled and it
-        // cannot be changed thereafter for consistency in dependents of the info.
-        _ASSERTE(callCountingInfo->GetStage() == CallCountingInfo::Stage::Disabled);
-        return;
-    }
-
-    NewHolder<CallCountingInfo> callCountingInfoHolder = CallCountingInfo::CreateWithCallCountingDisabled(codeVersion);
-    m_callCountingInfoByCodeVersionHash.Add(callCountingInfoHolder);
-    callCountingInfoHolder.SuppressRelease();
-}
-
 // Returns true if the code entry point was updated to reflect the active code version, false otherwise. In normal paths, the
 // code entry point is not updated only when the use of call counting stubs is disabled, as in that case returning to the
 // prestub is necessary for further call counting. On exception, the code entry point may or may not have been updated and it's
@@ -566,12 +488,7 @@ bool CallCountingManager::SetCodeEntryPoint(
     _ASSERTE(createTieringBackgroundWorkerRef == nullptr || !*createTieringBackgroundWorkerRef);
 
     if (!methodDesc->IsEligibleForTieredCompilation() ||
-        (
-            // For a default code version that is not tier 0, call counting will have been disabled by this time (checked
-            // below). Avoid the redundant and not-insignificant expense of GetOptimizationTier() on a default code version.
-            !activeCodeVersion.IsDefaultVersion() &&
-            activeCodeVersion.IsFinalTier()
-        ) ||
+        activeCodeVersion.IsFinalTier() ||
         !g_pConfig->TieredCompilation_CallCounting())
     {
         methodDesc->SetCodeEntryPoint(codeEntryPoint);
@@ -1148,11 +1065,6 @@ void CallCountingManager::DeleteAllCallCountingStubs()
         {
             CallCountingInfo *callCountingInfo = *it;
             CallCountingInfo::Stage callCountingStage = callCountingInfo->GetStage();
-            if (callCountingStage == CallCountingInfo::Stage::Disabled)
-            {
-                continue;
-            }
-
             if (callCountingInfo->GetCallCountingStub() != nullptr)
             {
                 callCountingInfo->ClearCallCountingStub();

src/coreclr/vm/callcounting.h

@@ -196,9 +196,6 @@ class CallCountingManager
 
             // Stub is not active and will not become active, call counting complete, promoted, stub may be deleted
             Complete,
-
-            // Call counting is disabled, only used for the default code version to indicate that it is to be optimized
-            Disabled
         };
 
     private:
@@ -208,10 +205,7 @@ class CallCountingManager
         Stage m_stage;
 
     #ifndef DACCESS_COMPILE
-    private:
-        CallCountingInfo(NativeCodeVersion codeVersion);
     public:
-        static CallCountingInfo *CreateWithCallCountingDisabled(NativeCodeVersion codeVersion);
         CallCountingInfo(NativeCodeVersion codeVersion, CallCount callCountThreshold);
         ~CallCountingInfo();
     #endif
@@ -336,13 +330,7 @@ class CallCountingManager
     static void StaticInitialize();
 #endif // !DACCESS_COMPILE
 
-public:
-    bool IsCallCountingEnabled(NativeCodeVersion codeVersion);
-
 #ifndef DACCESS_COMPILE
-public:
-    void DisableCallCounting(NativeCodeVersion codeVersion);
-
 public:
     static bool SetCodeEntryPoint(
         NativeCodeVersion activeCodeVersion,

src/coreclr/vm/codeversion.cpp

@@ -346,22 +346,28 @@ NativeCodeVersion::OptimizationTier NativeCodeVersion::GetOptimizationTier() con
     }
     else
     {
-        return TieredCompilationManager::GetInitialOptimizationTier(GetMethodDesc());
+        PTR_MethodDesc pMethodDesc = GetMethodDesc();
+        OptimizationTier tier = pMethodDesc->GetMethodDescOptimizationTier();
+        if (tier == OptimizationTier::OptimizationTierUnknown)
+        {
+            tier = TieredCompilationManager::GetInitialOptimizationTier(pMethodDesc);
+        }
+        return tier;
     }
 }
 
 #ifndef DACCESS_COMPILE
 void NativeCodeVersion::SetOptimizationTier(OptimizationTier tier)
 {
-    WRAPPER_NO_CONTRACT;
+    STANDARD_VM_CONTRACT;
+
     if (m_storageKind == StorageKind::Explicit)
     {
         AsNode()->SetOptimizationTier(tier);
     }
     else
     {
-        // State changes should have been made previously such that the initial tier is the new tier
-        _ASSERTE(TieredCompilationManager::GetInitialOptimizationTier(GetMethodDesc()) == tier);
+        GetMethodDesc()->SetMethodDescOptimizationTier(tier);
     }
 }
 #endif

src/coreclr/vm/codeversion.h

@@ -82,6 +82,7 @@ class NativeCodeVersion
         OptimizationTierOptimized, // may do less optimizations than tier 1
         OptimizationTier0Instrumented,
         OptimizationTier1Instrumented,
+        OptimizationTierUnknown = 0xFFFFFFFF
     };
 #ifdef FEATURE_TIERED_COMPILATION
     OptimizationTier GetOptimizationTier() const;

src/coreclr/vm/eeconfig.cpp

@@ -789,11 +789,35 @@ HRESULT EEConfig::sync()
         }
     #endif
 
+#ifdef FEATURE_PGO
+        if (fTieredPGO)
+        {
+            // Initial tier for R2R is always just OptimizationTier0
+            // For ILOnly it depends on TieredPGO_InstrumentOnlyHotCode:
+            // OptimizationTier0 as we don't want to instrument the initial version (will only instrument hot Tier0)
+            // OptimizationTier0Instrumented - instrument all ILOnly code
+            if (g_pConfig->TieredPGO_InstrumentOnlyHotCode())
+            {
+                tieredCompilation_DefaultTier = (DWORD)NativeCodeVersion::OptimizationTier0;
+            }
+            else
+            {
+                tieredCompilation_DefaultTier = (DWORD)NativeCodeVersion::OptimizationTier0Instrumented;
+            }
+        }
+        else
+#endif
+        {
+            tieredCompilation_DefaultTier = (DWORD)NativeCodeVersion::OptimizationTier0;
+        }
+
         if (ETW::CompilationLog::TieredCompilation::Runtime::IsEnabled())
         {
             ETW::CompilationLog::TieredCompilation::Runtime::SendSettings();
         }
     }
+#else // !FEATURE_TIERED_COMPILATION
+    tieredCompilation_DefaultTier = (DWORD)NativeCodeVersion::OptimizationTierOptimized;
 #endif
 
 #if defined(FEATURE_ON_STACK_REPLACEMENT)

src/coreclr/vm/eeconfig.h

@@ -96,6 +96,11 @@ class EEConfig
     bool          TieredCompilation_UseCallCountingStubs() const { LIMITED_METHOD_CONTRACT; return fTieredCompilation_UseCallCountingStubs; }
     DWORD         TieredCompilation_DeleteCallCountingStubsAfter() const { LIMITED_METHOD_CONTRACT; return tieredCompilation_DeleteCallCountingStubsAfter; }
 #endif // FEATURE_TIERED_COMPILATION
+    DWORD TieredCompilation_DefaultTier() const 
+    {
+        LIMITED_METHOD_CONTRACT;
+        return tieredCompilation_DefaultTier;
+    }
 
 #if defined(FEATURE_PGO)
     bool          TieredPGO(void) const { LIMITED_METHOD_CONTRACT;  return fTieredPGO; }
@@ -607,6 +612,7 @@ class EEConfig
     DWORD tieredCompilation_CallCountingDelayMs;
     DWORD tieredCompilation_DeleteCallCountingStubsAfter;
 #endif
+    DWORD tieredCompilation_DefaultTier;
 
 #if defined(FEATURE_PGO)
     bool fTieredPGO;

src/coreclr/vm/method.cpp

@@ -239,6 +239,10 @@ HRESULT MethodDesc::EnsureCodeDataExists(AllocMemTracker *pamTracker)
     if (alloc == NULL)
         return E_OUTOFMEMORY;
 
+#ifdef FEATURE_CODE_VERSIONING
+    alloc->OptimizationTier = NativeCodeVersion::OptimizationTierUnknown;
+#endif
+
     // Try to set the field. Suppress clean-up if we win the race.
     if (InterlockedCompareExchangeT(&m_codeData, (MethodDescCodeData*)alloc, NULL) == NULL)
         amTracker.SuppressRelease();
@@ -260,6 +264,16 @@ HRESULT MethodDesc::SetMethodDescVersionState(PTR_MethodDescVersioningState stat
 
     return S_OK;
 }
+
+void MethodDesc::SetMethodDescOptimizationTier(NativeCodeVersion::OptimizationTier tier)
+{
+    STANDARD_VM_CONTRACT;
+
+    IfFailThrow(EnsureCodeDataExists(NULL));
+
+    _ASSERTE(m_codeData != NULL);
+    VolatileStoreWithoutBarrier(&m_codeData->OptimizationTier, tier);
+}
 #endif // FEATURE_CODE_VERSIONING
 
 #ifdef FEATURE_INTERPRETER
@@ -297,6 +311,15 @@ PTR_MethodDescVersioningState MethodDesc::GetMethodDescVersionState()
         return NULL;
     return VolatileLoadWithoutBarrier(&codeData->VersioningState);
 }
+
+NativeCodeVersion::OptimizationTier MethodDesc::GetMethodDescOptimizationTier()
+{
+    WRAPPER_NO_CONTRACT;
+    PTR_MethodDescCodeData codeData = VolatileLoadWithoutBarrier(&m_codeData);
+    if (codeData == NULL)
+        return NativeCodeVersion::OptimizationTierUnknown;
+    return VolatileLoadWithoutBarrier(&codeData->OptimizationTier);
+}
 #endif // FEATURE_CODE_VERSIONING
 
 //*******************************************************************************

src/coreclr/vm/method.hpp

@@ -254,6 +254,7 @@ struct MethodDescCodeData final
 {
 #ifdef FEATURE_CODE_VERSIONING
     PTR_MethodDescVersioningState VersioningState;
+    NativeCodeVersion::OptimizationTier OptimizationTier;
 #endif // FEATURE_CODE_VERSIONING
     PCODE TemporaryEntryPoint;
 #ifdef FEATURE_INTERPRETER
@@ -1936,8 +1937,10 @@ class MethodDesc
 #ifdef FEATURE_CODE_VERSIONING
 #ifndef DACCESS_COMPILE
     HRESULT SetMethodDescVersionState(PTR_MethodDescVersioningState state);
+    void SetMethodDescOptimizationTier(NativeCodeVersion::OptimizationTier tier);
 #endif // !DACCESS_COMPILE
     PTR_MethodDescVersioningState GetMethodDescVersionState();
+    NativeCodeVersion::OptimizationTier GetMethodDescOptimizationTier();
 #endif // FEATURE_CODE_VERSIONING
 
 public:
@@ -2319,20 +2322,6 @@ class PrepareCodeConfig
 
 #ifdef FEATURE_TIERED_COMPILATION
 public:
-    bool WasTieringDisabledBeforeJitting() const
-    {
-        WRAPPER_NO_CONTRACT;
-        return m_wasTieringDisabledBeforeJitting;
-    }
-
-    void SetWasTieringDisabledBeforeJitting()
-    {
-        WRAPPER_NO_CONTRACT;
-        _ASSERTE(GetMethodDesc()->IsEligibleForTieredCompilation());
-
-        m_wasTieringDisabledBeforeJitting = true;
-    }
-
     bool ShouldCountCalls() const
     {
         WRAPPER_NO_CONTRACT;
@@ -2441,7 +2430,6 @@ class PrepareCodeConfig
 
 #ifdef FEATURE_TIERED_COMPILATION
 private:
-    bool m_wasTieringDisabledBeforeJitting;
     bool m_shouldCountCalls;
 #endif