Add per-request latency observer churn summaries

docs/remote-workspace-local-latency-observer-plan.md

@@ -162,14 +162,14 @@ Why it matters:
 
 Measure:
 
-- [ ] number of full-state pushes per request
+- [x] number of full-state pushes per request
 - [x] total full-state payload bytes per request
-- [ ] number of partial-message events per request
+- [x] number of partial-message events per request
 - [x] number of partial-message events per request
 - [x] total partial-message payload bytes per request
 - [ ] number of task UI deltas per request where supported
 - [x] number of task UI deltas per request where supported
-- [ ] persistence flush counts where supported
+- [x] persistence flush counts where supported
 
 Why it matters:
 
@@ -213,10 +213,10 @@ These should work on both `main` and `eve_troubleshooting-remote-workspaces` wit
 These may only exist natively on `eve_troubleshooting-remote-workspaces` or may require additional light plumbing on `main`:
 
 - [ ] chunk-to-webview timing
-- [ ] full-state post counts / bytes
-- [ ] partial-message event counts
-- [ ] task UI delta counts
-- [ ] persistence flush metrics
+- [x] full-state post counts / bytes
+- [x] partial-message event counts
+- [x] task UI delta counts
+- [x] persistence flush metrics
 
 ### Recommended implementation rule
 

src/services/latency/LatencyObserverService.ts

@@ -3,16 +3,27 @@ import {
 	DEFAULT_LATENCY_OBSERVER_CAPABILITIES,
 	type LatencyObserverCapabilities,
 	type LatencyObserverLogEntry,
+	type LatencyObserverRequestCounterSummary,
 	type LatencyObserverSessionMetadata,
 	type LatencyObserverStateSnapshot,
 	type LatencySample,
 } from "@/shared/LatencyObserver"
 
 type ActiveRequest = {
+	taskId: string
 	requestId: string
 	startedAt: number
 	firstVisibleRecorded: boolean
 	firstFullStateRecorded: boolean
+	counterBaseline: Record<
+		| "fullStatePushes"
+		| "fullStateBytes"
+		| "partialMessageEvents"
+		| "partialMessageBytes"
+		| "taskUiDeltaEvents"
+		| "persistenceFlushes",
+		number
+	>
 }
 
 export class LatencyObserverService {
@@ -34,6 +45,7 @@ export class LatencyObserverService {
 	private readonly requestStartSamples: LatencySample[] = []
 	private readonly firstVisibleUpdateSamples: LatencySample[] = []
 	private readonly firstFullStateUpdateSamples: LatencySample[] = []
+	private readonly requestCounterSummaries: LatencyObserverRequestCounterSummary[] = []
 	private readonly logs: LatencyObserverLogEntry[] = []
 	private optionalCounters: Record<
 		| "fullStatePushes"
@@ -87,10 +99,12 @@ export class LatencyObserverService {
 
 	markRequestStart(taskId: string, requestId: string, startedAt = performance.now()): void {
 		this.activeRequests.set(taskId, {
+			taskId,
 			requestId,
 			startedAt,
 			firstVisibleRecorded: false,
 			firstFullStateRecorded: false,
+			counterBaseline: { ...this.optionalCounters },
 		})
 		this.requestStartSamples.push({
 			startedAt,
@@ -141,6 +155,22 @@ export class LatencyObserverService {
 			return
 		}
 
+		this.requestCounterSummaries.push({
+			requestId: activeRequest.requestId,
+			taskId: activeRequest.taskId,
+			startedAt: activeRequest.startedAt,
+			completedAt: performance.now(),
+			fullStatePushes: this.optionalCounters.fullStatePushes - activeRequest.counterBaseline.fullStatePushes,
+			fullStateBytes: this.optionalCounters.fullStateBytes - activeRequest.counterBaseline.fullStateBytes,
+			partialMessageEvents: this.optionalCounters.partialMessageEvents - activeRequest.counterBaseline.partialMessageEvents,
+			partialMessageBytes: this.optionalCounters.partialMessageBytes - activeRequest.counterBaseline.partialMessageBytes,
+			taskUiDeltaEvents: this.optionalCounters.taskUiDeltaEvents - activeRequest.counterBaseline.taskUiDeltaEvents,
+			persistenceFlushes: this.optionalCounters.persistenceFlushes - activeRequest.counterBaseline.persistenceFlushes,
+		})
+		if (this.requestCounterSummaries.length > 50) {
+			this.requestCounterSummaries.shift()
+		}
+
 		this.activeRequests.delete(taskId)
 		this.pushLog(`request completed`, taskId, activeRequest.requestId)
 	}
@@ -182,6 +212,7 @@ export class LatencyObserverService {
 				samples: [...this.firstFullStateUpdateSamples],
 				stats: createRollingLatencyStats(this.firstFullStateUpdateSamples),
 			},
+			requestCounterSummaries: [...this.requestCounterSummaries],
 			logs: [...this.logs],
 			optionalCounters: { ...this.optionalCounters },
 		}
@@ -205,6 +236,7 @@ export class LatencyObserverService {
 		this.requestStartSamples.length = 0
 		this.firstVisibleUpdateSamples.length = 0
 		this.firstFullStateUpdateSamples.length = 0
+		this.requestCounterSummaries.length = 0
 		this.logs.length = 0
 		this.optionalCounters = {
 			fullStatePushes: 0,

src/services/latency/__tests__/LatencyObserverService.test.ts

@@ -64,6 +64,34 @@ describe("LatencyObserverService", () => {
 		assert.equal(snapshot.optionalCounters?.partialMessageBytes, 128)
 	})
 
+	it("captures per-request richer counter summaries on completion", () => {
+		const service = new LatencyObserverService()
+
+		service.markRequestStart("task-4", "task-4:req-1", 50)
+		service.incrementCounter("fullStatePushes", 2)
+		service.incrementCounter("fullStateBytes", 300)
+		service.incrementCounter("partialMessageEvents", 3)
+		service.incrementCounter("partialMessageBytes", 120)
+		service.incrementCounter("taskUiDeltaEvents", 4)
+		service.incrementCounter("persistenceFlushes", 1)
+		service.completeRequest("task-4")
+
+		const snapshot = service.getSnapshot()
+		assert.equal(snapshot.requestCounterSummaries.length, 1)
+		assert.deepEqual(snapshot.requestCounterSummaries[0], {
+			requestId: "task-4:req-1",
+			taskId: "task-4",
+			startedAt: 50,
+			completedAt: snapshot.requestCounterSummaries[0].completedAt,
+			fullStatePushes: 2,
+			fullStateBytes: 300,
+			partialMessageEvents: 3,
+			partialMessageBytes: 120,
+			taskUiDeltaEvents: 4,
+			persistenceFlushes: 1,
+		})
+	})
+
 	it("uses capability support values in metric snapshots", () => {
 		const service = new LatencyObserverService()
 
@@ -102,6 +130,7 @@ describe("LatencyObserverService", () => {
 		assert.equal(snapshot.requestStart.stats.count, 0)
 		assert.equal(snapshot.firstVisibleUpdate.stats.count, 0)
 		assert.equal(snapshot.firstFullStateUpdate.stats.count, 0)
+		assert.equal(snapshot.requestCounterSummaries.length, 0)
 		assert.equal(snapshot.logs.length, 0)
 		assert.equal(snapshot.optionalCounters?.fullStatePushes, 0)
 	})

src/shared/LatencyObserver.ts

@@ -67,6 +67,19 @@ export interface LatencyObserverMetricSnapshot {
 	stats: RollingLatencyStats
 }
 
+export interface LatencyObserverRequestCounterSummary {
+	requestId: string
+	taskId?: string
+	startedAt: number
+	completedAt: number
+	fullStatePushes: number
+	fullStateBytes: number
+	partialMessageEvents: number
+	partialMessageBytes: number
+	taskUiDeltaEvents: number
+	persistenceFlushes: number
+}
+
 export interface LatencyObserverLogEntry {
 	ts: number
 	message: string
@@ -82,6 +95,7 @@ export interface LatencyObserverStateSnapshot {
 	requestStart: LatencyObserverMetricSnapshot
 	firstVisibleUpdate: LatencyObserverMetricSnapshot
 	firstFullStateUpdate: LatencyObserverMetricSnapshot
+	requestCounterSummaries: LatencyObserverRequestCounterSummary[]
 	logs: LatencyObserverLogEntry[]
 	optionalCounters?: LatencyObserverMetricSet["optionalCounters"]
 }

webview-ui/src/components/settings/sections/DebugSection.spec.tsx

@@ -38,6 +38,18 @@ type MockLatencyObserverState = {
 	firstVisibleUpdate: MockLatencyObserverState["transport"]
 	firstFullStateUpdate: MockLatencyObserverState["transport"]
 	logs: unknown[]
+	requestCounterSummaries: Array<{
+		requestId: string
+		taskId?: string
+		startedAt: number
+		completedAt: number
+		fullStatePushes: number
+		fullStateBytes: number
+		partialMessageEvents: number
+		partialMessageBytes: number
+		taskUiDeltaEvents: number
+		persistenceFlushes: number
+	}>
 	optionalCounters?: {
 		fullStatePushes: number
 		fullStateBytes: number
@@ -88,6 +100,20 @@ const extensionStateMock = vi.hoisted(() => ({
 			stats: { count: 1, minMs: 14, maxMs: 14, avgMs: 14, lastMs: 14, totalMs: 14 },
 		},
 		logs: [],
+		requestCounterSummaries: [
+			{
+				requestId: "task-1:req-1",
+				taskId: "task-1",
+				startedAt: 10,
+				completedAt: 24,
+				fullStatePushes: 2,
+				fullStateBytes: 512,
+				partialMessageEvents: 3,
+				partialMessageBytes: 256,
+				taskUiDeltaEvents: 4,
+				persistenceFlushes: 1,
+			},
+		],
 		optionalCounters: {
 			fullStatePushes: 3,
 			fullStateBytes: 1024,
@@ -156,6 +182,20 @@ describe("DebugSection", () => {
 				stats: { count: 1, minMs: 14, maxMs: 14, avgMs: 14, lastMs: 14, totalMs: 14 },
 			},
 			logs: [],
+			requestCounterSummaries: [
+				{
+					requestId: "task-1:req-1",
+					taskId: "task-1",
+					startedAt: 10,
+					completedAt: 24,
+					fullStatePushes: 2,
+					fullStateBytes: 512,
+					partialMessageEvents: 3,
+					partialMessageBytes: 256,
+					taskUiDeltaEvents: 4,
+					persistenceFlushes: 1,
+				},
+			],
 			optionalCounters: {
 				fullStatePushes: 3,
 				fullStateBytes: 1024,
@@ -201,6 +241,8 @@ describe("DebugSection", () => {
 		expect(screen.getByText(/State pushes: 3/)).toBeTruthy()
 		expect(screen.getByText(/State bytes: 1024/)).toBeTruthy()
 		expect(screen.getByText(/Partial bytes: 256/)).toBeTruthy()
+		expect(screen.getByText(/Req state pushes: 2/)).toBeTruthy()
+		expect(screen.getByText(/Req partial bytes: 256/)).toBeTruthy()
 		expect(screen.getByText(/Transport probe: Supported/)).toBeTruthy()
 		expect(screen.getByText(/First full-state avg: 14.00 ms/)).toBeTruthy()
 		expect(screen.getByText(/Task UI delta metrics: Unsupported on this branch/)).toBeTruthy()

webview-ui/src/components/settings/sections/DebugSection.tsx

@@ -60,6 +60,7 @@ const DebugSection = ({ onResetState, renderSectionHeader }: DebugSectionProps)
 		OBSERVATION_SCENARIOS.find((scenario) => scenario.id === selectedScenarioId) ?? OBSERVATION_SCENARIOS[0]
 
 	const transportSamples = latencyObserver?.transport.samples ?? []
+	const latestRequestSummary = latencyObserver?.requestCounterSummaries.at(-1)
 	const effectiveTransportSamples = useMemo(() => {
 		if (transportSamples.length > 0) {
 			return transportSamples
@@ -307,6 +308,17 @@ const DebugSection = ({ onResetState, renderSectionHeader }: DebugSectionProps)
 							<div>Partial bytes: {latencyObserver.optionalCounters?.partialMessageBytes ?? 0}</div>
 							<div>Task UI deltas: {latencyObserver.optionalCounters?.taskUiDeltaEvents ?? 0}</div>
 							<div>Persistence flushes: {latencyObserver.optionalCounters?.persistenceFlushes ?? 0}</div>
+							{latestRequestSummary && (
+								<>
+									<div className="font-medium text-foreground">Latest request churn</div>
+									<div>Req state pushes: {latestRequestSummary.fullStatePushes}</div>
+									<div>Req state bytes: {latestRequestSummary.fullStateBytes}</div>
+									<div>Req partial events: {latestRequestSummary.partialMessageEvents}</div>
+									<div>Req partial bytes: {latestRequestSummary.partialMessageBytes}</div>
+									<div>Req UI deltas: {latestRequestSummary.taskUiDeltaEvents}</div>
+									<div>Req persistence flushes: {latestRequestSummary.persistenceFlushes}</div>
+								</>
+							)}
 							<div className="max-h-24 overflow-auto rounded border border-[var(--vscode-panel-border)] p-2">
 								{latencyObserver.logs.length === 0
 									? "No observer events yet."