Migrate 'ts.performance' to use native performance hooks when available

Author: rbuckton

src/compiler/performance.ts

@@ -2,15 +2,12 @@
 /** Performance measurements for the compiler. */
 namespace ts.performance {
     declare const onProfilerEvent: { (markName: string): void; profiler: boolean; };
+    const profilerEvent: (markName: string) => void = typeof onProfilerEvent === "function" && onProfilerEvent.profiler === true ? onProfilerEvent : noop;
 
-    // NOTE: cannot use ts.noop as core.ts loads after this
-    const profilerEvent: (markName: string) => void = typeof onProfilerEvent === "function" && onProfilerEvent.profiler === true ? onProfilerEvent : () => { /*empty*/ };
-
+    let perfHooks: PerformanceHooks | undefined;
+    let perfObserver: PerformanceObserver | undefined;
+    let perfEntryList: PerformanceObserverEntryList | undefined;
     let enabled = false;
-    let profilerStart = 0;
-    let counts: ESMap<string, number>;
-    let marks: ESMap<string, number>;
-    let measures: ESMap<string, number>;
 
     export interface Timer {
         enter(): void;
@@ -53,9 +50,8 @@ namespace ts.performance {
      * @param markName The name of the mark.
      */
     export function mark(markName: string) {
-        if (enabled) {
-            marks.set(markName, timestamp());
-            counts.set(markName, (counts.get(markName) || 0) + 1);
+        if (perfHooks && enabled) {
+            perfHooks.performance.mark(markName);
             profilerEvent(markName);
         }
     }
@@ -70,10 +66,8 @@ namespace ts.performance {
      *      used.
      */
     export function measure(measureName: string, startMarkName?: string, endMarkName?: string) {
-        if (enabled) {
-            const end = endMarkName && marks.get(endMarkName) || timestamp();
-            const start = startMarkName && marks.get(startMarkName) || profilerStart;
-            measures.set(measureName, (measures.get(measureName) || 0) + (end - start));
+        if (perfHooks && enabled) {
+            perfHooks.performance.measure(measureName, startMarkName, endMarkName);
         }
     }
 
@@ -83,7 +77,7 @@ namespace ts.performance {
      * @param markName The name of the mark.
      */
     export function getCount(markName: string) {
-        return counts && counts.get(markName) || 0;
+        return perfEntryList?.getEntriesByName(markName, "mark").length || 0;
     }
 
     /**
@@ -92,7 +86,7 @@ namespace ts.performance {
      * @param measureName The name of the measure whose durations should be accumulated.
      */
     export function getDuration(measureName: string) {
-        return measures && measures.get(measureName) || 0;
+        return perfEntryList?.getEntriesByName(measureName, "measure").reduce((a, entry) => a + entry.duration, 0) || 0;
     }
 
     /**
@@ -101,22 +95,25 @@ namespace ts.performance {
      * @param cb The action to perform for each measure
      */
     export function forEachMeasure(cb: (measureName: string, duration: number) => void) {
-        measures.forEach((measure, key) => {
-            cb(key, measure);
+        perfEntryList?.getEntriesByType("measure").forEach(entry => {
+            cb(entry.name, entry.duration);
         });
     }
 
     /** Enables (and resets) performance measurements for the compiler. */
     export function enable() {
-        counts = new Map<string, number>();
-        marks = new Map<string, number>();
-        measures = new Map<string, number>();
-        enabled = true;
-        profilerStart = timestamp();
+        if (!enabled) {
+            perfHooks ||= tryGetNativePerformanceHooks() || ShimPerformance?.createPerformanceHooksShim(timestamp);
+            if (!perfHooks) throw new Error("TypeScript requires an environment that provides a compatible native Web Performance API implementation.");
+            perfObserver ||= new perfHooks.PerformanceObserver(list => perfEntryList = list);
+            perfObserver.observe({ entryTypes: ["mark", "measure"] });
+            enabled = true;
+        }
     }
 
     /** Disables performance measurements for the compiler. */
     export function disable() {
+        perfObserver?.disconnect();
         enabled = false;
     }
 }

src/compiler/performanceCore.ts

@@ -0,0 +1,80 @@
+/*@internal*/
+namespace ts {
+    export interface PerformanceHooks {
+        performance: Performance;
+        PerformanceObserver: PerformanceObserverConstructor;
+    }
+
+    export interface Performance {
+        clearMarks(name?: string): void;
+        mark(name: string): void;
+        measure(name: string, startMark?: string, endMark?: string): void;
+        now(): number;
+        timeOrigin: number;
+    }
+
+    export interface PerformanceEntry {
+        name: string;
+        entryType: string;
+        startTime: number;
+        duration: number;
+    }
+
+    export interface PerformanceObserverEntryList {
+        getEntries(): PerformanceEntryList;
+        getEntriesByName(name: string, type?: string): PerformanceEntryList;
+        getEntriesByType(type: string): PerformanceEntryList;
+    }
+
+    export interface PerformanceObserver {
+        disconnect(): void;
+        observe(options: { entryTypes: readonly string[] }): void;
+    }
+
+    export type PerformanceObserverConstructor = new (callback: (list: PerformanceObserverEntryList, observer: PerformanceObserver) => void) => PerformanceObserver;
+    export type PerformanceEntryList = PerformanceEntry[];
+
+    declare const performance: Performance | undefined;
+    declare const PerformanceObserver: PerformanceObserverConstructor | undefined;
+
+    function tryGetWebPerformanceHooks(): PerformanceHooks | undefined {
+        if (typeof performance === "object" &&
+            typeof performance.timeOrigin === "number" &&
+            typeof performance.clearMarks === "function" &&
+            typeof performance.mark === "function" &&
+            typeof performance.measure === "function" &&
+            typeof performance.now === "function" &&
+            typeof PerformanceObserver === "function") {
+            return {
+                performance,
+                PerformanceObserver
+            };
+        }
+    }
+
+    function tryGetNodePerformanceHooks(): PerformanceHooks | undefined {
+        if (typeof module === "object" && typeof require === "function") {
+            try {
+                return require("perf_hooks") as typeof import("perf_hooks");
+            }
+            catch {
+                // ignore errors
+            }
+        }
+    }
+
+    const nativePerformanceHooks = tryGetWebPerformanceHooks() || tryGetNodePerformanceHooks();
+
+    export function tryGetNativePerformanceHooks() {
+        return nativePerformanceHooks;
+    }
+
+    /** Gets a timestamp with (at least) ms resolution */
+    export const timestamp = (() => {
+        if (nativePerformanceHooks) {
+            const performance = nativePerformanceHooks.performance;
+            return () => performance.now();
+        }
+        return Date.now ? Date.now : () => +(new Date());
+    })();
+}

src/compiler/performanceTimestamp.ts

@@ -13,7 +13,7 @@
         "corePublic.ts",
         "core.ts",
         "debug.ts",
-        "performanceTimestamp.ts",
+        "performanceCore.ts",
         "performance.ts",
         "perfLogger.ts",
         "semver.ts",

src/compiler/tsconfig.json

@@ -1204,7 +1204,7 @@ interface Array<T> { length: number; [n: number]: T; }`
 
     function baselineOutputs(baseline: string[], output: readonly string[], start: number, end = output.length) {
         for (let i = start; i < end; i++) {
-            baseline.push(output[i].replace(/Elapsed::\s[0-9]+ms/g, "Elapsed:: *ms"));
+            baseline.push(output[i].replace(/Elapsed::\s[0-9]+(?:\.\d+)?ms/g, "Elapsed:: *ms"));
         }
     }