Enum TraceEventKind
Discriminant for a trace record. Every record starts with a 12-byte common header whose third byte carries this value; the kind determines how the bytes after the header are interpreted (span header or minimal instant header, then per-kind typed payload).
public enum TraceEventKind : byte- Extension Methods
Fields
BTreeDelete = 41B+Tree delete. No payload.
BTreeInsert = 40B+Tree insert. No payload — kind is the only data.
BTreeNodeMerge = 43B+Tree node merge. No payload.
BTreeNodeSplit = 42B+Tree node split. No payload.
CheckpointCollect = 84Checkpoint phase: collect dirty page indices.
CheckpointCycle = 83Full checkpoint cycle. Required:
targetLsn: i64,reason: u8(CheckpointReason). Optional:dirtyPageCount: i32.CheckpointFsync = 86Checkpoint phase: fsync data file.
CheckpointRecycle = 88Checkpoint phase: recycle WAL segments below checkpoint LSN. Optional:
recycledCount: i32.CheckpointTransition = 87Checkpoint phase: transition UoW entries from WalDurable to Committed. Optional:
transitionedCount: i32.CheckpointWrite = 85Checkpoint phase: write dirty pages to data file. Optional:
writtenCount: i32.ClusterMigration = 60Cluster migration between spatial cells. Required:
archetypeId: u16,migrationCount: i32.ConcurrencyAccessControlContention = 95AccessControl contention marker — flag-set instant, fires when a thread enters a wait. Payload: empty.
ConcurrencyAccessControlExclusiveAcquire = 92AccessControl exclusive (writer) acquire success. Payload:
threadId: u16,hadToWait: u8,elapsedUs: u16.ConcurrencyAccessControlExclusiveRelease = 93AccessControl exclusive (writer) release. Payload:
threadId: u16.ConcurrencyAccessControlPromotion = 94AccessControl shared→exclusive promotion (or exclusive→shared demotion via variant byte). Payload:
elapsedUs: u16,variant: u8(0=promote, 1=demote).AccessControl shared (reader) acquire success. Payload:
threadId: u16,hadToWait: u8,elapsedUs: u16.AccessControl shared (reader) release. Payload:
threadId: u16.ConcurrencyAccessControlSmallContention = 100AccessControlSmall contention marker. Payload: empty.
ConcurrencyAccessControlSmallExclusiveAcquire = 98AccessControlSmall exclusive acquire. Payload:
threadId: u16.ConcurrencyAccessControlSmallExclusiveRelease = 99AccessControlSmall exclusive release. Payload:
threadId: u16.AccessControlSmall shared acquire. Payload:
threadId: u16.AccessControlSmall shared release. Payload:
threadId: u16.ConcurrencyAdaptiveWaiterYieldOrSleep = 112AdaptiveWaiter Wait() call yielded or slept (transition only — NOT per-spin). Payload:
spinCountBefore: u16,kind: u8(1=yield, 2=sleep).ConcurrencyEpochAdvance = 108GlobalEpoch advance (Interlocked.Increment in ExitScope/ExitScopeUnordered). Payload:
newEpoch: u32.ConcurrencyEpochRefresh = 109RefreshScope — bump epoch mid-scope to release retired memory while staying pinned. Payload:
oldEpoch: u32,newEpoch: u32.ConcurrencyEpochScopeEnter = 106EpochGuard scope enter (PinCurrentThread). Payload:
currentEpoch: u32,depthBefore: u8,isDormantToActive: u8.ConcurrencyEpochScopeExit = 107EpochGuard scope exit (Dispose). Payload:
newEpoch: u32,isOutermost: u8.ConcurrencyEpochSlotClaim = 110EpochThreadRegistry slot claim. Payload:
slotIndex: u16,threadId: u16,activeCount: u16.ConcurrencyEpochSlotReclaim = 111EpochThreadRegistry dead-thread slot reclaim. Payload:
slotIndex: u16,oldOwner: u16,newOwner: u16.ConcurrencyOlcLatchMarkObsolete = 115OlcLatch.MarkObsolete — node retired, future readers will fail validation. Payload:
version: u32.ConcurrencyOlcLatchValidationFail = 116OlcLatch.ValidateVersion failed — version mismatch detected on optimistic re-read. Payload:
expectedVersion: u32,actualVersion: u32.ConcurrencyOlcLatchWriteLockAttempt = 113OlcLatch.TryWriteLock failed (raced or write-locked). Payload:
versionBefore: u32,success: u8(always 0 on emit).ConcurrencyOlcLatchWriteUnlock = 114OlcLatch.WriteUnlock — version bumped from oldVersion to newVersion. Payload:
oldVersion: u32,newVersion: u32.ConcurrencyResourceAccessing = 101ResourceAccessControl Accessing-mode acquire (try or wait). Payload:
success: u8,accessingCount: u8,elapsedUs: u16.ConcurrencyResourceContention = 105ResourceAccessControl contention marker. Payload: empty.
ConcurrencyResourceDestroy = 103ResourceAccessControl Destroy-mode acquire. Payload:
success: u8,elapsedUs: u16.ConcurrencyResourceModify = 102ResourceAccessControl Modify-mode acquire (try or wait). Payload:
success: u8,threadId: u16,elapsedUs: u16.ConcurrencyResourceModifyPromotion = 104ResourceAccessControl Modify promotion slow path (wait for accessors to drain). Payload:
elapsedUs: u16.DataIndexBTreeBulkInsert = 184BTree multi-value bulk-insert span. Payload:
bufferId: i32, entryCount: i32.DataIndexBTreeNodeCow = 186BTree node CoW (PreDirtyForWrite triggered). Payload:
srcChunkId: i32, dstChunkId: i32.DataIndexBTreeRangeScan = 181BTree range-scan span (covers the whole enumeration). Payload:
resultCount: i32, restartCount: u8.DataIndexBTreeRangeScanRevalidate = 182BTree range-scan OLC revalidate instant (per restart). Payload:
restartCount: u8.DataIndexBTreeRebalanceFallback = 183BTree pessimistic fallback after OLC failure. Payload:
reason: u8(0=LeafFull, 1=OlcFail).DataIndexBTreeRoot = 185BTree root operation (Init or Split, merged via op variant). Payload:
op: u8(0=Init, 1=Split),rootChunkId: i32, height: u8.DataIndexBTreeSearch = 180BTree FindLeaf slow-path instant (b-link hop / OLC restart). Payload:
retryReason: u8, restartCount: u8.DataMvccChainWalk = 178MVCC chain-walk slow path (only emitted when full walk runs, not the single-entry fast path). Payload:
tsn: i64, chainLen: u8, visibility: u8.DataMvccVersionCleanup = 179MVCC version-cleanup span. Payload:
pk: i64, entriesFreed: u16.DataTransactionCleanup = 177Transaction Cleanup span — wraps deferred-cleanup batch enqueue. Payload:
tsn: i64, entityCount: i32.DataTransactionConflict = 176Transaction Conflict instant — fired only when an actual conflict is detected during commit. Payload:
tsn: i64, pk: i64, componentTypeId: i32, conflictType: u8.DataTransactionInit = 173Transaction Init / snapshot acquire span. Payload:
tsn: i64, uowId: u16.DataTransactionPrepare = 174Transaction PrepareForMutation span (high-freq; default-suppressed). Payload:
tsn: i64.DataTransactionValidate = 175Transaction Validate span — wraps the commit-loop validation pass. Payload:
tsn: i64, entryCount: i32.DurabilityCheckpointBackpressure = 223Checkpoint staging-exhaustion backpressure span. Payload:
waitMs: u32, exhausted: u8.DurabilityCheckpointSleep = 224Checkpoint between-cycle sleep span. Payload:
sleepMs: u32, wakeReason: u8.DurabilityCheckpointWriteBatch = 222Checkpoint write-batch span. Payload:
writeBatchSize: i32, stagingAllocated: i32.DurabilityRecoveryDiscover = 226Recovery discover/enumerate WAL segments. Payload:
segCount: i32, totalBytes: i64, firstSegId: i32.DurabilityRecoveryFpi = 229Recovery FPI torn-page repair span. Payload:
fpiCount: i32, repairedCount: i32, mismatches: i32.DurabilityRecoveryRecord = 228Recovery per-record decode/apply (extreme-freq, deny-listed). Payload:
chunkType: u8, lsn: i64, size: i32.DurabilityRecoveryRedo = 230Recovery redo replay span. Payload:
recordsReplayed: i32, uowsReplayed: i32, durUs: u32.DurabilityRecoverySegment = 227Recovery per-segment scan. Payload:
segId: i32, recCount: i32, bytes: i64, truncated: u8.DurabilityRecoveryStart = 225Recovery start instant. Payload:
checkpointLsn: i64, reason: u8.DurabilityRecoveryTickFence = 232Recovery TickFence replay span. Payload:
tickFenceCount: i32, entries: i32, tickNumber: i64.DurabilityRecoveryUndo = 231Recovery undo (voided UoWs) span. Payload:
voidedUowCount: i32.DurabilityUowDeadline = 234UoW deadline check instant. Payload:
deadline: i64, remaining: i64, expired: u8.DurabilityUowState = 233UoW state transition instant. Payload:
from: u8, to: u8, uowId: u16, reason: u8.DurabilityWalBackpressure = 221WAL commit-buffer-full backpressure span. Payload:
waitUs: u32, producerThread: i32.DurabilityWalBuffer = 219WAL staging-buffer copy span. Payload:
bytesAligned: i32, pad: i32.DurabilityWalFrame = 220WAL per-frame CRC instant (extreme-freq, deny-listed). Payload:
frameCount: u16, crcStart: u32.DurabilityWalGroupCommit = 217WAL group-commit boundary instant. Payload:
triggerMs: u16, producerThread: i32.DurabilityWalOsWrite = 215WAL flush phase 2: OS write + fsync. Payload:
bytesAligned: i32, frameCount: i32, highLsn: i64.DurabilityWalQueue = 218WAL drain decision instant. Payload:
drainAttempt: u8, dataLen: i32, waitReason: u8.DurabilityWalQueueDrain = 214WAL flush phase 1: drain coalesce. Payload:
bytesAligned: i32, frameCount: i32.DurabilityWalSignal = 216WAL flush phase 3: LSN advance + signal. Payload:
highLsn: i64.EcsDestroy = 31Entity destroy. Required:
entityId: u64. Optional:cascadeCount: i32,tsn: i64.EcsQueryAny = 34Query any. Required:
archetypeTypeId: u16. Optional:found: bool,scanMode: u8.EcsQueryConstraintEnabled = 202EcsQuery Enabled/Disabled constraint add. Payload:
typeId: u16, enableBit: u8.EcsQueryConstruct = 199EcsQuery construct (archetype resolution). Payload:
targetArchId: u16, polymorphic: u8, maskSize: u8.EcsQueryCount = 33Query count. Required:
archetypeTypeId: u16. Optional:resultCount: i32,scanMode: u8.EcsQueryExecute = 32Query execute. Required:
archetypeTypeId: u16. Optional:resultCount: i32,scanMode: u8.EcsQueryMaskAnd = 200EcsQuery mask AND. Payload:
bitsBefore: u16, bitsAfter: u16, opType: u8.EcsQuerySpatialAttach = 203EcsQuery spatial predicate attach. Payload:
spatialType: u8, queryBox: 4xf32 (x1, y1, x2, y2).EcsQuerySubtreeExpand = 201EcsQuery subtree expand. Payload:
subtreeCount: u16, rootId: u16.EcsSpawn = 30Entity spawn. Required:
archetypeId: u16. Optional:entityId: u64,tsn: i64.EcsViewDeltaBufferOverflow = 206View delta-buffer overflow (operationally critical — never default-suppressed). Payload:
currentTsn: i64, tailTsn: i64, marginPagesLost: u16.EcsViewDeltaCacheMiss = 213View delta-cache miss (entity re-eval). Payload:
pk: i64, reason: u8.EcsViewIncrementalDrain = 205View IncrementalDrain. Payload:
deltaCount: i32, overflow: u8.EcsViewProcessEntry = 207View single-branch entry process (instant, high-freq, default-suppressed). Payload:
pk: i64, fieldIdx: u16, pass: u8.EcsViewProcessEntryOr = 208View OR-mode entry process (instant, high-freq, default-suppressed). Payload:
pk: i64, branchCount: u8, bitmapDelta: u32.EcsViewRefresh = 35View refresh. Required:
archetypeTypeId: u16. Optional:mode: u8,resultCount: i32,deltaCount: i32.EcsViewRefreshFull = 209View Refresh-from-overflow (Pull). Payload:
oldCount: i32, newCount: i32, requeryNs: u32.EcsViewRefreshFullOr = 210View RefreshFullOr. Payload:
oldCount: i32, newCount: i32, branchCount: u8.EcsViewRefreshPull = 204View RefreshPull (full re-query branch). Payload:
queryNs: u32, archetypeMaskBits: u16.EcsViewRegistryDeregister = 212ViewRegistry Deregister. Payload:
viewId: u16, fieldIdx: u16, regCount: u16.EcsViewRegistryRegister = 211ViewRegistry Register. Payload:
viewId: u16, fieldIdx: u16, regCount: u16.GcEnd = 8.NET runtime GC boundary — a garbage collection has ended. Payload:
u8 generation,u32 count,i64 pauseDurationTicks,u64 promotedBytes, fiveu64per-generation size-after values (Gen0/Gen1/Gen2/LOH/POH),u64 totalCommittedBytes. Sizes are snapshotted by the ingestion thread via GetGCMemoryInfo() on theGCEnd_V1event.GcStart = 7.NET runtime GC boundary — a garbage collection has started. Payload:
u8 generation,u8 reason(GcReason),u8 type(GcType),u32 count. Emitted by the profiler's GC ingestion thread on observingGCStart_V2. Only produced whenTelemetryConfig.ProfilerGcTracingActiveis set at class load.GcSuspension = 75.NET runtime Execution-Engine suspension window. Opened on
GCSuspendEEBegin_V1(ETW id 9), closed onGCRestartEEEnd_V1(ETW id 3). Payload:u8 reason(GcSuspendReason),u8 optMask(reserved).ParentSpanIdis always 0 (process-level, not caller-attributed). No Activity capture.Instant = 6Generic instant marker. Payload:
nameId: i32(interned),payload: i32.MemoryAlignmentWaste = 172Alignment-induced waste on an allocation (only emitted when waste > 0). Payload:
size: i32, alignment: i32, wastePctHundredths: u16.MemoryAllocEvent = 9Discrete unmanaged-memory allocation or free event. Every
PinnedMemoryBlockconstruct/dispose emits one of these whenTelemetryConfig.ProfilerMemoryAllocationsActiveis set. Payload:u8 direction(MemoryAllocDirection),u16 sourceTag(MemoryAllocSource),u64 sizeBytes,u64 totalAfterBytes. Wire size: 31 B.NamedSpan = 246User-defined span with inline UTF-8 null-terminated name. Used for dynamic-string call sites (tests, demo code). Payload: null-terminated UTF-8 bytes.
Was
200until 2026-05-10, which collided with EcsQueryMaskAnd. The collision was latent in production becauseEcsQueryMaskAndis default-suppressed, but unsuppressing it would have made the two kinds indistinguishable on the wire. Reassigned to 246 (next free slot above SchedulerSystemArchetype). Wire format bumped to v8 in CurrentVersion to signal the change.PageCacheAllocatePage = 53Page cache allocate page. Required:
filePageIndex: i32.PageCacheBackpressure = 59Page cache backpressure wait — clock-sweep retry loop couldn't find a free page. Required:
retryCount: i32,dirtyCount: i32,epochCount: i32. Suppressed by default alongside other PageCache.* kinds.PageCacheDiskRead = 51Page cache disk read. Required:
filePageIndex: i32.PageCacheDiskReadCompleted = 56Completion marker for an async PageCacheDiskRead. Required:
filePageIndex: i32. The record carries the original DiskRead span'sSpanIdas its ownSpanId(same value — the viewer uses this to correlate kickoff → completion) and aStartTimestampequal to the original'sStartTimestamp, so the record'sdurationTicksfield is the full async tail:completionTimestamp - beginTimestamp. Emitted from the thread-pool worker that completes theRandomAccess.ReadAsync.Suppressed by default alongside the other PageCache.* kinds. Opt in with
TyphonEvent.UnsuppressKind(PageCacheDiskReadCompleted)(must ALSO have PageCacheDiskRead unsuppressed, otherwise there's no kickoff span to correlate with and the completion is skipped at the call site). Reuses PageCacheEventCodec wire shape verbatim — decoder needs only a match-arm entry.PageCacheDiskWrite = 52Page cache disk write. Required:
filePageIndex: i32. Optional:pageCount: i32.PageCacheDiskWriteCompleted = 57Completion marker for an async PageCacheDiskWrite. Required:
filePageIndex: i32. Same correlation pattern as PageCacheDiskReadCompleted — record'sSpanIdmatches the original DiskWrite span,durationTicksis the full async tail including the OS write completion.PageCacheFetch = 50Page cache fetch. Required:
filePageIndex: i32.PageCacheFlush = 54Page cache flush. Required:
pageCount: i32.PageCacheFlushCompleted = 58Completion marker for an async PageCacheFlush. Required:
pageCount: i32(stored in the primaryfilePageIndexslot per Flush convention). Record'sdurationTickscovers the full flush tail:max(WriteAsync completions)+fsync. The delta between this record's duration and the max of the enclosed PageCacheDiskWriteCompleted events is pure fsync cost.PageEvicted = 55A cached page was displaced by PageCacheAllocatePage to make room for a new page being fetched. Required:
filePageIndex: i32(the displaced page's file index, NOT the incoming page).Emitted as a zero-duration span (start == end). Parents under the enclosing PageCacheAllocatePage span via TLS, so the viewer renders eviction events as instant markers nested inside the AllocatePage bar — "allocation ran for 12 µs and kicked out page N." Reuses the
PageCacheEventCodecwire shape (common header + span extension + 4 B filePageIndex + 1 B optMask), so no new codec is needed. Suppressed by default alongside the other PageCache.* kinds.PerTickSnapshot = 76Per-tick gauge snapshot — packed bundle of (gaugeId, value) pairs emitted once per tick by the scheduler thread at end-of-tick. Instant-style record: no span header extension, no duration semantics. Common header + fixed prefix (
u32 tickNumber,u16 fieldCount,u32 flags) then repeated{u16 gaugeId; u8 valueKind; [4 or 8 B] value}entries. Gated onTelemetryConfig.ProfilerGaugesActive. See GaugeId for the wire-stable gauge ID registry.Although this kind's numeric value is ≥ 10, it is not a span record. IsSpan(TraceEventKind) explicitly excludes it so the consumer never tries to read the 25-byte span header extension after the common header.
PhaseEnd = 3Tick phase ended. Payload:
phase: u8.PhaseStart = 2Tick phase started. Payload:
phase: u8(TickPhase enum).QueryArgs = 248Per-execution arguments payload emitted immediately after each QueryPlan when the query carries at least one evaluator (skipped when
EvaluatorCount == 0). Payload:evaluatorCount: u16,thresholds[evaluatorCount]: i64(widened threshold constants matchingFieldEvaluator.Threshold).QueryCount = 198Count-only path. Payload:
resultCount: i32.QueryDefinitionDescribe = 247One-shot definition descriptor emitted on first observation of a View/EcsQuery identity within a profiling session. Payload (variable-length):
kind: u8(0=View, 1=EcsQuery),localId: u32,targetComponentType: u16,primaryIndexFieldIdx: i16,sortFieldIdx: i16,sortDescending: u8,definitionSourceFileId: u16,definitionSourceLine: i32,definitionSourceMethodId: u16,evaluatorCount: u16,evaluators[evaluatorCount]: { fieldIdx: u16, op: u8, reserved: u8 },fieldDependencyCount: u16,fieldDependencies[fieldDependencyCount]: u16.QueryEstimate = 190Selectivity estimate. Payload:
fieldIdx: u16, cardinality: i64.QueryExecuteFilter = 195Filter pass (post-primary). Payload:
filterCount: u8, rejectedCount: i32.QueryExecuteIndexScan = 193B+Tree range-scan dispatch. Payload:
primaryFieldIdx: u16, mode: u8(0=Single, 1=Multi).QueryExecuteIterate = 194Index iteration (chunk-grain). Payload:
chunkCount: i32, entryCount: i32.QueryExecutePagination = 196Pagination (Skip/Take). Payload:
skip: i32, take: i32, earlyTerm: u8.QueryExecuteStorageMode = 197Storage-mode dispatch instant. Payload:
mode: u8(0=SV, 1=Versioned, 2=Transient).QueryParse = 187Query expression parse. Payload:
predicateCount: u16, branchCount: u8.QueryParseDnf = 188Query DNF normalization. Payload:
inBranches: u16, outBranches: u16.QueryPlan = 189Query plan build. Payload:
evaluatorCount: u8, indexFieldIdx: u16, rangeMin: i64, rangeMax: i64.QueryPlanPrimarySelect = 191Primary stream selection (instant). Payload:
candidates: u8, winnerIdx: u8, reason: u8.QueryPlanSort = 192Predicate ordering / sort by cardinality. Payload:
evaluatorCount: u8, sortNs: u32.QueueTickEnd = 244Per-(tick, queue) rollup emitted at end-of-tick. Captures queue-depth telemetry that's local to the engine's
EventQueueBaseaccumulators (peak depth, end-of-tick depth, overflow count, produced/consumed counts). Folded by IncrementalCacheBuilder into the v12 QueueTickSummaries section for the Workbench Data APIqueue/<name>tracks (#311). Payload:tick: u32, queueId: u16, peakDepth: u32, endOfTickDepth: u32, overflowCount: u32, produced: u32, consumed: u32= 26 bytes after the common header.RuntimePhaseSpan = 243Tick lifecycle phase span — covers the full duration of one TickPhase region inside
TyphonRuntime.OnTickEndInternal(SystemDispatch, WriteTickFence, UoWFlush, OutputPhase, TierIndexRebuild, DormancySweep). Replaces the previous PhaseStart+PhaseEnd instant pair on the producer side: a real span is opened at the top ofInspectorPhaseand disposed at the bottom, so child spans (PageCacheFlush,BTreeInsert, etc.) attach viaparentSpanIdfor proper hierarchy. Payload:phase: u8(TickPhase enum).RuntimePhaseUoWCreate = 161UoW create (per tick, OnTickStart). Payload:
tick: i64.RuntimePhaseUoWFlush = 162UoW flush (per tick, OnTickEnd). Payload:
tick: i64,changeCount: i32.RuntimeSubscriptionDeltaBuild = 236Delta-builder span. Payload:
viewId: u16, added: i32, removed: i32, modified: i32.RuntimeSubscriptionDeltaDirtyBitmapSupplement = 240Dirty-bitmap supplement span (when ring overflows). Payload:
modifiedFromRing: i32, supplementCount: i32, unionSize: i32.RuntimeSubscriptionDeltaSerialize = 237Per-client delta serialize span (high-freq, deny-listed). Payload:
clientId: u32, viewId: u16, bytes: i32, format: u8.RuntimeSubscriptionOutputCleanup = 239Dead-client cleanup span. Payload:
deadCount: i32, deregCount: i32.RuntimeSubscriptionOutputExecute = 164Subscription output phase (per tick). Payload:
tick: i64,level: u8,clientCount: u16,viewsRefreshed: u16,deltasPushed: u32,overflowCount: u16.RuntimeSubscriptionSubscriber = 235Per-subscriber invocation span (high-freq, deny-listed). Payload:
subscriberId: u32, viewId: u16, deltaCount: i32.RuntimeSubscriptionTransitionBeginSync = 238Subscription transition (BeginSync) span. Payload:
clientId: u32, viewId: u16, entitySnapshot: i32.RuntimeTransactionLifecycle = 163Per-system Transaction lifecycle span. Payload:
sysIdx: u16,txDurUs: u32,success: u8.SchedulerChunk = 10Scheduler chunk executed on a worker. Payload:
systemIdx: u16,chunkIdx: u16,totalChunks: u16,entitiesProcessed: i32.SchedulerDependencyFanOut = 155Dependency fan-out span over OnSystemComplete successor loop. Payload:
completingSysIdx: u16,succCount: u16,skippedCount: u16.SchedulerDependencyReady = 154Successor mark-ready (only when depsLeft → 0). Payload:
fromSysIdx: u16,toSysIdx: u16,fanOut: u16,predRemain: u16.SchedulerDispense = 153Successful chunk-grab CAS. Payload:
sysIdx: u16,chunkIdx: i32,workerId: u8.SchedulerGraphBuild = 159DAG build at startup. Payload:
sysCount: u16,edgeCount: u16,topoLen: u16.SchedulerGraphRebuild = 160DAG rebuild (dynamic system registration — design stub, no producer in Phase 4). Payload:
oldSysCount: u16,newSysCount: u16,reason: u8.SchedulerMetronomeWait = 241Metronome wait between ticks (TickDriver thread, Sleep→Yield→Spin phases). Span covers the entire gap from the moment
ExecuteCallbacksreturned (or timer started) until the next tick fires. Payload:scheduledTimestamp: i64, multiplier: u8, intentClass: u8, phaseFlags: u8(11 B).intentClass: 0=CatchUp (target already past), 1=Throttled (mult>1), 2=Headroom (mult==1 normal idle).phaseFlagsbits: 0x1=Sleep entered, 0x2=Yield entered, 0x4=Spin entered.SchedulerOverloadDetector = 242Per-tick OverloadDetector state snapshot (instant on TickDriver). Carries the full state used to drive escalation/deescalation decisions so an offline trace can audit why the engine throttled. Payload:
tick: i64, overrunRatio: f32, consecutiveOverrun: u16, consecutiveUnderrun: u16, consecutiveQueueGrowth: u16, queueDepth: i32, level: u8, multiplier: u8(24 B).SchedulerOverloadLevelChange = 156Overload level transition (only on change). Payload:
prevLvl: u8,newLvl: u8,ratio: f32,queueDepth: i32,oldMul: u8,newMul: u8.SchedulerOverloadSystemShed = 157Per-system shed/throttle decision (when overload level > Normal). Payload:
sysIdx: u16,level: u8,divisor: u16,decision: u8(0=shouldRunFalse, 1=throttled, 2=shed).SchedulerOverloadTickMultiplier = 158Tick multiplier applied (per tick). Payload:
tick: i64,multiplier: u8,intervalTicks: u8.SchedulerSystemArchetype = 245Per-(system, archetype) entity-touch rollup emitted at parallel-query completion. Captures the cross-dimension that SchedulerChunk (per-system) and EcsQueryExecute (per-archetype) leave separate. Feeds the Workbench Data Flow module's
archetype/,system-archetype/, andcomponent-family/*track families. Payload:systemIndex: u16, archetypeId: u16, entityCount: i32, chunkCount: i32= 12 bytes after the span header. Gated byTelemetryConfig.SchedulerArchetypeTouchesActive.SchedulerSystemCompletion = 147System completion (RecordSystemDone). Payload:
sysIdx: u16,reason: u8(0=ok, 1..N=SkipReason),durationUs: u32.SchedulerSystemQueueWait = 148Ready → first-grab latency (queue wait). Payload:
sysIdx: u16,queueWaitUs: u32.SchedulerSystemSingleThreaded = 149Single-threaded system execution span. Payload:
sysIdx: u16,isParallelQuery: u8,chunkCount: u16.SchedulerSystemStartExecution = 146System first chunk dispatched — execution boundary (after CAS, before work). Payload:
sysIdx: u16.SchedulerWorkerBetweenTick = 152Worker between-tick wait (kernel wait span). Payload:
workerId: u8,waitUs: u32,wakeReason: u8(0=signal, 1=shutdown).SchedulerWorkerIdle = 150Worker idle span (per spin spell). Payload:
workerId: u8,spinCount: u16,idleUs: u32.SchedulerWorkerWake = 151Worker wake from kernel signal. Payload:
workerId: u8,delayUs: u32.SpatialCellIndexAdd = 130CellSpatialIndex.Add — append cluster to cell's SoA. Payload:
cellKey: i32,slot: i32,clusterChunkId: i32,capacity: i32.SpatialCellIndexRemove = 132CellSpatialIndex.RemoveAt — swap-with-last. Payload:
cellKey: i32,slot: i32,swappedClusterId: i32.SpatialCellIndexUpdate = 131CellSpatialIndex.UpdateAt — in-place AABB rewrite at slot. Payload:
cellKey: i32,slot: i32.SpatialClusterAabbRefresh = 250Per-tick span around
RecomputeDirtyClusterAabbs. Fires once per archetype per tick — the existing SpatialCellIndexUpdate instant fires per per-cell index UpdateAt, but doesn't show the cost of the full pass (occupancy scan + bit-exact compare for unchanged clusters). Required payload:archetypeId: u16,clusterScanned: i32,aabbChanged: i32. Gated onSpatialCellIndexUpdateActive.SpatialClusterMigrationDetect = 133Cluster migration detected (cell crossing observed, queued for execute). Payload:
archetypeId: u16,clusterChunkId: i32,oldCellKey: i32,newCellKey: i32.SpatialClusterMigrationDetectScan = 249Per-tick span around
DetectClusterMigrations. Fires once per archetype per tick whenever the spatial path runs, regardless of whether any entity actually crossed a cell — the existing SpatialClusterMigrationDetect instant only fires per detected crossing, so it's silent for workloads where ants/units move within hysteresis every tick (e.g. AntHill). Required payload:archetypeId: u16,scanSlotCount: i32(slots iterated),migrationsQueued: i32,hysteresisAbsorbed: i32. Gated onSpatialClusterMigrationDetectActive.SpatialClusterMigrationHysteresis = 135Cluster migration hysteresis absorb — crossing detected but absorbed by margin (no migration queued). Payload:
archetypeId: u16,clusterChunkId: i32,escapeDistSq: f32.SpatialClusterMigrationQueue = 134Cluster migration queue append. Payload:
archetypeId: u16,clusterChunkId: i32,queueLen: u16.SpatialGridCellTierChange = 127Cell tier change (only emits when SetCellTier actually flips the tier byte). Payload:
cellKey: i32,oldTier: u8,newTier: u8.SpatialGridClusterCellAssign = 129Cluster-cell assignment (cluster claimed in a particular cell). Payload:
clusterChunkId: i32,cellKey: i32,archetypeId: u16.SpatialGridOccupancyChange = 128Cell occupancy change (Increment/Decrement merged via signed delta). Payload:
cellKey: i32,delta: i8,occBefore: u16,occAfter: u16.SpatialMaintainAabbValidate = 140Degenerate AABB validation failure. Payload:
entityPK: i64,componentTypeId: u16,opcode: u8(0=insert, 1=update, 2=remove).SpatialMaintainBackPointerWrite = 141Spatial back-pointer write (componentChunkId → leafChunkId+slotIndex). Payload:
componentChunkId: i32,leafChunkId: i32,slotIndex: u16.SpatialMaintainInsert = 138Maintain.InsertSpatial — wraps RTree.Insert + back-pointer + occupancy. Payload:
entityPK: i64,componentTypeId: u16,didDegenerate: u8.SpatialMaintainUpdateSlowPath = 139Maintain.UpdateSpatial slow-path — escape detected, remove + reinsert. Payload:
entityPK: i64,componentTypeId: u16,escapeDistSq: f32.SpatialQueryAabb = 117AABB query iterator pass. Payload:
nodesVisited: u16,leavesEntered: u16,resultCount: u16,restartCount: u8,categoryMask: u32.SpatialQueryCount = 122Count query (CountInAABB / CountInRadius merged via variant byte). Payload:
variant: u8(0=AABB, 1=Radius),nodesVisited: u16,resultCount: i32.SpatialQueryFrustum = 120Frustum query iterator pass. Payload:
nodesVisited: u16,resultCount: u16,planeCount: u8,restartCount: u8.SpatialQueryKnn = 121KNN query (full call covering all radius-expansion iterations). Payload:
k: u16,iterCount: u8,finalRadius: f32,resultCount: u16.SpatialQueryRadius = 118Radius (sphere) query iterator pass. Payload:
nodesVisited: u16,resultCount: u16,radius: f32,restartCount: u8.SpatialQueryRay = 119Ray query iterator pass. Payload:
nodesVisited: u16,resultCount: u16,maxDist: f32,restartCount: u8.SpatialRTreeBulkLoad = 126RTree bulk-load (init-time). Payload:
entityCount: i32,leafCount: i32.SpatialRTreeInsert = 123RTree insert (descent + leaf write or split fallout). Payload:
entityId: i64,depth: u8,didSplit: u8,restartCount: u8.SpatialRTreeNodeSplit = 125RTree node split (sub-event of Insert when leaf is full). Payload:
depth: u8,splitAxis: u8,leftCount: u8,rightCount: u8.SpatialRTreeRemove = 124RTree remove (leaf modify, possibly cascade up). Payload:
entityId: i64,leafCollapse: u8.SpatialTierIndexRebuild = 136TierClusterIndex rebuild span. Payload:
archetypeId: u16,clusterCount: i32,oldVersion: i32,newVersion: i32.SpatialTierIndexVersionSkip = 137TierClusterIndex version-skip — rebuild bypassed because version unchanged. Payload:
archetypeId: u16,version: i32,reason: u8.SpatialTriggerCacheInvalidate = 145Trigger static-tree cache invalidate (mutation observed bumps cached version). Payload:
regionId: u16,oldVersion: i32,newVersion: i32.SpatialTriggerEval = 143Trigger region eval span. Payload:
regionId: u16,occupantCount: u16,enterCount: u16,leaveCount: u16.SpatialTriggerOccupantDiff = 144Trigger occupant XOR-diff stats (NO bitmap). Payload:
regionId: u16,prevCount: u16,currCount: u16,enterCount: u16,leaveCount: u16.SpatialTriggerRegion = 142Trigger region create/destroy (merged via op variant). Payload:
op: u8(0=create, 1=destroy),regionId: u16,categoryMask: u32.StatisticsRebuild = 89Statistics rebuild for a ComponentTable. Required:
entityCount: i32,mutationCount: i32,samplingInterval: i32.StorageChunkSegmentGrow = 169ChunkBasedSegment.Grow. Payload:
stride: i32, oldCap: i32, newCap: i32.StorageFileHandle = 170File handle Open/Close (merged via op variant). Payload:
op: u8(0=open, 1=close),filePathId: i32, modeOrReason: u8.StorageOccupancyMapGrow = 171OccupancyMap L3 grow path. Payload:
oldCap: i32, newCap: i32.StoragePageCacheDirtyWalk = 165Dirty-walk during checkpoint (collect dirty page indices). Payload:
rangeStart: i32, rangeLen: i32, dirtyMs: i32.StorageSegmentCreate = 166LogicalSegment.Create. Payload:
segmentId: i32, pageCount: i32.StorageSegmentGrow = 167LogicalSegment.Grow. Payload:
segmentId: i32, oldLen: i32, newLen: i32.StorageSegmentLoad = 168LogicalSegment.Load. Payload:
segmentId: i32, pageCount: i32.SystemReady = 4A system became ready (all predecessors completed). Payload:
systemIdx: u16,predecessorCount: u16.SystemSkipped = 5A system was skipped. Payload:
systemIdx: u16,skipReason: u8.ThreadContextSwitch = 254OS thread context-switch — closes one ON-CPU slice for a Typhon-registered thread. Instant-style record produced by
EtwSchedulingPump. Payload:u8 targetSlotIdx(slot to re-attribute to, NOT the producer slot),u8 processorNumber,u8 waitReason(ThreadWaitReason),u8 threadState(post-switch System.Diagnostics.ThreadState),u8 gettingIdle(1 = CPU went to System Idle next),u32 durationQpc(QPC ticks the slice held the CPU, capped at uint.MaxValue ≈ 7 min),u32 readyTimeQpc(QPC ticks on the ready queue before this slice; 0 = unknown, uint.MaxValue = saturated). Common-header timestamp = the slice's START QPC tick. Gated onRuntimeThreadSchedulingActive.ThreadInfo = 77Per-slot thread identity — emitted once when a producer thread claims its slot. Carries the managed thread ID and a UTF-8 thread name so the viewer can label lanes with something meaningful ("DagScheduler", "TyphonProfilerConsumer", pool worker name, ...) instead of just the numeric slot index. Wire layout after the 12-byte common header:
i32 managedThreadId,u16 nameByteCount,byte[nameByteCount] nameUtf8. Instant-style (no span-header extension); see IsSpan(TraceEventKind).TickEnd = 1Scheduler tick ended. Payload:
overloadLevel: u8,tickMultiplier: u8.TickStart = 0Scheduler tick started (empty payload). Emitted at the top of each
DagScheduler.RunTick.TransactionCommit = 20Transaction commit. Required:
tsn: i64. Optional:componentCount: i32,conflictDetected: bool.TransactionCommitComponent = 22Per-component commit sub-span. Required:
tsn: i64,componentTypeId: i32.TransactionPersist = 23WAL serialization inside Transaction.Commit. Required:
tsn: i64. Optional:walLsn: i64.TransactionRollback = 21Transaction rollback. Required:
tsn: i64. Optional:componentCount: i32.WalFlush = 80WAL writer drain-write-signal cycle. Required:
batchByteCount: i32,frameCount: i32,highLsn: i64.WalSegmentRotate = 81WAL segment rotation. Required:
newSegmentIndex: i32.WalWait = 82Thread blocked waiting for WAL durability. Required:
targetLsn: i64. Emitted on the calling thread, not the WAL writer.WriteTickFenceCluster = 61Per-tick span around the per-archetype body inside
WriteClusterTickFence. Covers both the has-dirty branch (snapshot + occupancy mask + shadow + spatial + WAL serialize + dormancy sweep) and the clean branch (dormancy sweep + optional spatial AABB refresh on local occupancy bitmap). Required payload:archetypeId: u16. Optional payload:dirtyClusterCount: i32,entryCount: i32,hasShadow: u8,hasSpatial: u8,walPublished: u8. Gated onRuntimeWriteTickFenceClusterActive.WriteTickFenceClusterShadow = 62Per-tick span around
ProcessClusterShadowEntriesfor one cluster-eligible archetype. Drains per-index shadow buffers for cluster-backed B+Tree indexes. Required payload:archetypeId: u16,dirtyClusterCount: i32. Optional payload:totalShadowEntries: i32. Gated onRuntimeWriteTickFenceClusterShadowActive.WriteTickFenceClusterSpatial = 63Per-tick span around the cluster spatial-maintenance block:
DetectClusterMigrations+ExecuteMigrations+RecomputeDirtyClusterAabbsfor one archetype with a Dynamic spatial slot. Parent of the fine-grained spans SpatialClusterMigrationDetectScan + SpatialClusterAabbRefresh + ClusterMigration. Required payload:archetypeId: u16,dirtyClusterCount: i32. Optional:migrationsExecuted: i32. Gated onRuntimeWriteTickFenceClusterSpatialActive.WriteTickFenceShadow = 252Per-tick span around
ProcessShadowEntriesfor one ComponentTable (deferred index maintenance for non-Versioned indexed fields with shadow buffers). Required payload:componentTypeId: u16,indexedFieldCount: i32. Optional payload:totalShadowEntries: i32(sum of buffer counts across all indexed fields). Gated onRuntimeWriteTickFenceShadowActive.WriteTickFenceSpatial = 253Per-tick span around
ProcessSpatialEntriesfor one ComponentTable (R-Tree position update for dirty entities). Required payload:componentTypeId: u16,dirtyEntryCount: i32. Optional payload:escapedCount: i32(entities whose new position escaped their fat AABB and got reinserted). Gated onRuntimeWriteTickFenceSpatialActive.WriteTickFenceTable = 251Per-tick span around the per-ComponentTable body inside
WriteTickFenceCore(WAL serialize + shadow + spatial + archive). Fires once per dirty SV/Transient table per tick. Required payload:componentTypeId: u16,dirtyEntryCount: i32. Optional payload:walPublished: u8(0/1),hasShadow: u8(0/1),hasSpatial: u8(0/1). Gated onRuntimeWriteTickFenceTableActive.
Remarks
Wire stability: numeric values are part of the .typhon-trace file format. Never renumber or reuse an ID — append new entries only.
Gaps in numbering are intentional so related categories can grow contiguously without renumbering existing kinds.
Span vs instant: kinds < 10 are instant events — they carry only the 12-byte common header plus optional minimal payload, no span extension (no duration, no spanId, no parent linkage). Kinds ≥ 10 are span events — they include the 25-byte span header extension plus an optional 16-byte trace context and per-kind typed payload. Use IsSpan(TraceEventKind) for the range check.