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Rework and simplify initial versioning and tiering rules #125243

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e69a0de
Rework and simplify initial versioning and tiering rules
davidwrighton Mar 5, 2026
c639ff0
Update src/coreclr/vm/method.cpp
davidwrighton Mar 5, 2026
12130e6
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davidwrighton Mar 6, 2026
12209cf
Merge branch 'rework_and_simplify_initial_versioning_rules' of github…
davidwrighton Mar 6, 2026
0632f9d
Simplify initial versioning rules in tiered compilation
davidwrighton Mar 6, 2026
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90 changes: 1 addition & 89 deletions src/coreclr/vm/callcounting.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -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),
Expand Down Expand Up @@ -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;
}
Expand Down Expand Up @@ -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;
Expand All @@ -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)
Expand Down Expand Up @@ -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
Expand Down Expand Up @@ -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);
Expand Down Expand Up @@ -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();
Expand Down
12 changes: 0 additions & 12 deletions src/coreclr/vm/callcounting.h
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Original file line number Diff line number Diff line change
Expand Up @@ -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:
Expand All @@ -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
Expand Down Expand Up @@ -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,
Expand Down
14 changes: 10 additions & 4 deletions src/coreclr/vm/codeversion.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand Down
1 change: 1 addition & 0 deletions src/coreclr/vm/codeversion.h
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Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand Down
24 changes: 24 additions & 0 deletions src/coreclr/vm/eeconfig.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -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 = NativeCodeVersion::OptimizationTierOptimized;
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Copilot AI Mar 6, 2026

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In the !FEATURE_TIERED_COMPILATION branch, tieredCompilation_DefaultTier (a DWORD) is assigned an enum value without an explicit cast, while other assignments in this method cast to DWORD. Using a consistent explicit cast here helps avoid compiler warnings (and matches the nearby code style).

Suggested change
tieredCompilation_DefaultTier = NativeCodeVersion::OptimizationTierOptimized;
tieredCompilation_DefaultTier = (DWORD)NativeCodeVersion::OptimizationTierOptimized;

Copilot uses AI. Check for mistakes.
#endif

#if defined(FEATURE_ON_STACK_REPLACEMENT)
Expand Down
6 changes: 6 additions & 0 deletions src/coreclr/vm/eeconfig.h
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Original file line number Diff line number Diff line change
Expand Up @@ -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; }
Expand Down Expand Up @@ -607,6 +612,7 @@ class EEConfig
DWORD tieredCompilation_CallCountingDelayMs;
DWORD tieredCompilation_DeleteCallCountingStubsAfter;
#endif
DWORD tieredCompilation_DefaultTier;

#if defined(FEATURE_PGO)
bool fTieredPGO;
Expand Down
23 changes: 23 additions & 0 deletions src/coreclr/vm/method.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -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();
Expand All @@ -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
Expand Down Expand Up @@ -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

//*******************************************************************************
Expand Down
18 changes: 3 additions & 15 deletions src/coreclr/vm/method.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand Down Expand Up @@ -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:
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -2441,7 +2430,6 @@ class PrepareCodeConfig

#ifdef FEATURE_TIERED_COMPILATION
private:
bool m_wasTieringDisabledBeforeJitting;
bool m_shouldCountCalls;
#endif

Expand Down
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