perf(rolldown): reduce stalls on cold session open

packages/rolldown/src/node/rolldown/__tests__/cold-open-cache.test.ts

@@ -0,0 +1,67 @@
+import type { Event } from '@rolldown/debug'
+import { describe, expect, it } from 'vitest'
+import { createPluginBuildMetricsSummary, RolldownEventsManager } from '../events-manager'
+import { stringifyInSlices } from '../log-cache'
+
+const base = { build_id: 'bid_1', session_id: 'sid_1' }
+
+function hookCalls(callId: string, pluginId: number, module: string, time: number): Record<string, unknown>[] {
+  const plugin = { plugin_name: `plugin-${pluginId}`, plugin_id: pluginId, trigger: 'automatic', ...base }
+  return [
+    { timestamp: time, action: 'HookResolveIdCallStart', importer: null, module_request: module, import_kind: 'import-statement', call_id: `${callId}-r`, ...plugin },
+    { timestamp: time + 1, action: 'HookResolveIdCallEnd', resolved_id: module, is_external: false, call_id: `${callId}-r`, ...plugin },
+    { timestamp: time + 2, action: 'HookLoadCallStart', module_id: module, call_id: `${callId}-l`, ...plugin },
+    { timestamp: time + 5, action: 'HookLoadCallEnd', module_id: module, content: null, call_id: `${callId}-l`, ...plugin },
+    { timestamp: time + 6, action: 'HookTransformCallStart', module_id: module, content: 'a', call_id: `${callId}-t`, ...plugin },
+    { timestamp: time + 9, action: 'HookTransformCallEnd', module_id: module, content: 'bb', call_id: `${callId}-t`, ...plugin },
+  ]
+}
+
+function expectSummariesMatchCalls(manager: RolldownEventsManager) {
+  expect(manager.plugin_build_metrics.size).toBeGreaterThan(0)
+  const expected = new Map(Array.from(manager.plugin_build_metrics, ([id, metrics]) => [id, createPluginBuildMetricsSummary(metrics)]))
+  expect(manager.plugin_build_summaries).toEqual(expected)
+}
+
+describe('plugin summaries accumulated while parsing', () => {
+  it('match summaries computed from the recorded calls, also after a restore', () => {
+    const manager = new RolldownEventsManager()
+    const events = [
+      { timestamp: 1, action: 'BuildStart', ...base },
+      ...hookCalls('a', 1, '/src/a.ts', 10),
+      ...hookCalls('b', 2, '/src/b.ts', 20),
+      ...hookCalls('c', 1, '/src/c.ts', 40),
+      // An end without a matching start isn't recorded, so it must not be counted either.
+      { timestamp: 60, action: 'HookTransformCallEnd', module_id: '/src/a.ts', content: 'x', call_id: 'missing', plugin_name: 'plugin-1', plugin_id: 1, trigger: 'automatic', ...base },
+    ]
+    for (const event of events)
+      manager.handleEvent(event as unknown as Event)
+
+    expectSummariesMatchCalls(manager)
+    expect(manager.plugin_build_summaries.get(1)!.total.count).toBe(6)
+
+    // Restoring a snapshot (package summary cache) rebuilds the summaries.
+    const restored = new RolldownEventsManager()
+    restored.restore(manager.snapshot())
+    expect(restored.plugin_build_summaries).toEqual(manager.plugin_build_summaries)
+  })
+})
+
+describe('sliced cache serialization', () => {
+  it('produces the same JSON as JSON.stringify', async () => {
+    const large = Array.from({ length: 1100 }, (_, index) => index % 7 === 0
+      ? undefined
+      : {
+          id: `m${index} "quoted" \u2028 ä`,
+          skipped: undefined,
+          nested: index % 5 ? [index, null, undefined, { deep: [1, 2] }] : Array.from({ length: 1100 }, (_, i) => i),
+          fn: () => index,
+          // eslint-disable-next-line no-new-wrappers, unicorn/new-for-builtins
+          boxed: new String(`s${index}`),
+          date: new Date(index),
+        })
+    const value = { version: 3, log: { size: 1, mtime: 2 }, data: { metrics: large, empty: [], text: 'x' }, missing: undefined }
+
+    expect((await stringifyInSlices(value)).join('')).toBe(JSON.stringify(value))
+  })
+})

packages/rolldown/src/node/rolldown/events-manager.ts

@@ -63,6 +63,62 @@ function getContentInfo(content: string | null | undefined): ContentInfo {
   }
 }
 
+export interface PluginMetricSummary {
+  count: number
+  duration: number
+}
+
+export interface PluginBuildMetricsSummary {
+  plugin_id: number
+  plugin_name: string
+  total: PluginMetricSummary
+  resolve: PluginMetricSummary
+  load: PluginMetricSummary
+  transform: PluginMetricSummary
+}
+
+function createMetricSummary(): PluginMetricSummary {
+  return {
+    count: 0,
+    duration: 0,
+  }
+}
+
+function addMetricSummary(summary: PluginMetricSummary, duration: number) {
+  summary.count += 1
+  summary.duration += duration
+}
+
+function createEmptyPluginBuildMetricsSummary(pluginId: number, pluginName: string): PluginBuildMetricsSummary {
+  return {
+    plugin_id: pluginId,
+    plugin_name: pluginName,
+    total: createMetricSummary(),
+    resolve: createMetricSummary(),
+    load: createMetricSummary(),
+    transform: createMetricSummary(),
+  }
+}
+
+function addPluginCallToSummary(summary: PluginBuildMetricsSummary, call: Pick<PluginBuildMetrics['calls'][number], 'type' | 'duration'>) {
+  addMetricSummary(summary.total, call.duration)
+  if (call.type === 'resolve')
+    addMetricSummary(summary.resolve, call.duration)
+  else if (call.type === 'load')
+    addMetricSummary(summary.load, call.duration)
+  else if (call.type === 'transform')
+    addMetricSummary(summary.transform, call.duration)
+}
+
+export function createPluginBuildMetricsSummary(metrics: PluginBuildMetrics): PluginBuildMetricsSummary {
+  const summary = createEmptyPluginBuildMetricsSummary(metrics.plugin_id, metrics.plugin_name)
+
+  for (const call of metrics.calls)
+    addPluginCallToSummary(summary, call)
+
+  return summary
+}
+
 export function getContentRef(content: unknown) {
   return typeof content === 'string' && content.startsWith('$ref:')
     ? content.slice(5)
@@ -106,6 +162,8 @@ export class RolldownEventsManager {
   module_build_hook_events: Map<string, PendingModuleBuildHookEvent> = new Map()
   module_build_metrics: Map<string, ModuleBuildMetrics> = new Map()
   plugin_build_metrics: Map<number, PluginBuildMetrics> = new Map()
+  // Kept in step with `plugin_build_metrics`, so writing the plugin summary cache doesn't rescan every call.
+  plugin_build_summaries: Map<number, PluginBuildMetricsSummary> = new Map()
   build_start_time: number = 0
   build_end_time: number = 0
 
@@ -124,6 +182,15 @@ export class RolldownEventsManager {
       : getContentInfo(undefined)
   }
 
+  private addPluginCallSummary(pluginId: number, pluginName: string, duration: number, type: PluginBuildMetrics['calls'][number]['type']) {
+    let summary = this.plugin_build_summaries.get(pluginId)
+    if (!summary) {
+      summary = createEmptyPluginBuildMetricsSummary(pluginId, pluginName)
+      this.plugin_build_summaries.set(pluginId, summary)
+    }
+    addPluginCallToSummary(summary, { type, duration })
+  }
+
   recordBuildMetrics(event: ModuleBuildHookEvents) {
     if (MODULE_BUILD_START_HOOKS.includes(event.action)) {
       if (event.action === 'HookResolveIdCallStart') {
@@ -225,6 +292,8 @@ export class RolldownEventsManager {
           })
         }
         this.plugin_build_metrics.set(pluginId, plugin_build_metrics)
+        // Every branch above either returned or recorded a call.
+        this.addPluginCallSummary(pluginId, event.plugin_name, info.duration, plugin_build_metrics.calls.at(-1)!.type)
         this.module_build_metrics.set(module_id, module_build_metrics)
       }
     }
@@ -320,6 +389,7 @@ export class RolldownEventsManager {
     this.module_build_hook_events.clear()
     this.module_build_metrics.clear()
     this.plugin_build_metrics.clear()
+    this.plugin_build_summaries.clear()
     this.build_start_time = 0
     this.build_end_time = 0
   }
@@ -360,6 +430,7 @@ export class RolldownEventsManager {
       build_metrics: this.module_build_metrics.get(id),
     }]))
     this.plugin_build_metrics = new Map(snapshot.plugin_build_metrics)
+    this.plugin_build_summaries = new Map(snapshot.plugin_build_metrics.map(([pluginId, metrics]) => [pluginId, createPluginBuildMetricsSummary(metrics)]))
     this.build_start_time = snapshot.build_start_time
     this.build_end_time = snapshot.build_end_time
   }