test: make test-perf-hooks more robust and work with workers

Previously the test makes several assumptions about the absolute
values of the nodeTiming fields, which can make the test flaky
on slow machines. This patch rewrites the test to check the
relative values instead. It also updates the test to make it
work with workers instead of directly skipping in workers.
PR-URL: #49197
Refs: nodejs/reliability#638
Reviewed-By: Debadree Chatterjee <debadree333@gmail.com>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>

Author: joyeecheung

test/sequential/test-perf-hooks.js

@@ -1,84 +1,165 @@
 'use strict';
 
 constcommon=require('../common');
-constassert=require('assert');
 const{ performance }=require('perf_hooks');
+// Get the start time as soon as possible.
+consttestStartTime=performance.now();
+constassert=require('assert');
+const{ writeSync }=require('fs');
 
-if(!common.isMainThread)
-common.skip('bootstrapping workers works differently');
+// Use writeSync to stdout to avoid disturbing the loop.
+functionlog(str){
+writeSync(1,str+'\n');
+}
 
 assert(performance);
 assert(performance.nodeTiming);
 assert.strictEqual(typeofperformance.timeOrigin,'number');
+
+assert(testStartTime>0,`${testStartTime} <= 0`);
 // Use a fairly large epsilon value, since we can only guarantee that the node
 // process started up in 15 seconds.
-assert(Math.abs(performance.timeOrigin-Date.now())<15000);
+assert(testStartTime<15000,`${testStartTime} >= 15000`);
 
-constinited=performance.now();
-assert(inited<15000);
+// Use different ways to calculate process uptime to check that
+// performance.timeOrigin and performance.now() are in reasonable range.
+constepsilon=50;
+{
+constuptime1=Date.now()-performance.timeOrigin;
+constuptime2=performance.now();
+constuptime3=process.uptime()*1000;
+assert(Math.abs(uptime1-uptime2)<epsilon,
+`Date.now() - performance.timeOrigin (${uptime1}) - `+
+`performance.now() (${uptime2}) = `+
+`${uptime1-uptime2} >= +- ${epsilon}`);
+assert(Math.abs(uptime1-uptime3)<epsilon,
+`Date.now() - performance.timeOrigin (${uptime1}) - `+
+`process.uptime() * 1000 (${uptime3}) = `+
+`${uptime1-uptime3} >= +- ${epsilon}`);
+}
 
 assert.strictEqual(performance.nodeTiming.name,'node');
 assert.strictEqual(performance.nodeTiming.entryType,'node');
 
-constdelay=250;
-functioncheckNodeTiming(props){
-console.log(props);
-
-for(constpropofObject.keys(props)){
-if(props[prop].around!==undefined){
-assert.strictEqual(typeofperformance.nodeTiming[prop],'number');
-constdelta=performance.nodeTiming[prop]-props[prop].around;
-assert(
-Math.abs(delta)<(props[prop].delay||delay),
-`${prop}: ${Math.abs(delta)} >= ${props[prop].delay||delay}`
-);
-}else{
-assert.strictEqual(performance.nodeTiming[prop],props[prop],
-`mismatch for performance property ${prop}: `+
-`${performance.nodeTiming[prop]} vs ${props[prop]}`);
-}
-}
+// Copy all the values from the getters.
+constinitialTiming={ ...performance.nodeTiming};
+
+{
+const{
+ startTime,
+ nodeStart,
+ v8Start,
+ environment,
+ bootstrapComplete,
+}=initialTiming;
+
+assert.strictEqual(startTime,0);
+assert.strictEqual(typeofnodeStart,'number');
+assert(nodeStart>0,`nodeStart ${nodeStart} <= 0`);
+// The whole process starts before this test starts.
+assert(nodeStart<testStartTime,
+`nodeStart ${nodeStart} >= ${testStartTime}`);
+
+assert.strictEqual(typeofv8Start,'number');
+assert(v8Start>0,`v8Start ${v8Start} <= 0`);
+// V8 starts after the process starts.
+assert(v8Start>nodeStart,`v8Start ${v8Start} <= ${nodeStart}`);
+// V8 starts before this test starts.
+assert(v8Start<testStartTime,
+`v8Start ${v8Start} >= ${testStartTime}`);
+
+assert.strictEqual(typeofenvironment,'number');
+assert(environment>0,`environment ${environment} <= 0`);
+// Environment starts after V8 starts.
+assert(environment>v8Start,
+`environment ${environment} <= ${v8Start}`);
+// Environment starts before this test starts.
+assert(environment<testStartTime,
+`environment ${environment} >= ${testStartTime}`);
+
+assert.strictEqual(typeofbootstrapComplete,'number');
+assert(bootstrapComplete>0,`bootstrapComplete ${bootstrapComplete} <= 0`);
+// Bootstrap completes after environment starts.
+assert(bootstrapComplete>environment,
+`bootstrapComplete ${bootstrapComplete} <= ${environment}`);
+// Bootstrap completes before this test starts.
+assert(bootstrapComplete<testStartTime,
+`bootstrapComplete ${bootstrapComplete} >= ${testStartTime}`);
 }
 
-checkNodeTiming({
-name: 'node',
-entryType: 'node',
-startTime: 0,
-duration: {around: performance.now()},
-nodeStart: {around: 0},
-v8Start: {around: 0},
-bootstrapComplete: {around: inited,delay: 2500},
-environment: {around: 0},
-loopStart: -1,
-loopExit: -1
-});
+functioncheckNodeTiming(timing){
+// Calculate the difference between now() and duration as soon as possible.
+constnow=performance.now();
+constdelta=Math.abs(now-timing.duration);
+
+log(JSON.stringify(timing,null,2));
+// Check that the properties are still reasonable.
+assert.strictEqual(timing.name,'node');
+assert.strictEqual(timing.entryType,'node');
+
+// Check that duration is positive and practically the same as
+// performance.now() i.e. measures Node.js instance up time.
+assert.strictEqual(typeoftiming.duration,'number');
+assert(timing.duration>0,`timing.duration ${timing.duration} <= 0`);
+assert(delta<10,
+`now (${now}) - timing.duration (${timing.duration}) = ${delta} >= 10`);
+
+// Check that the following fields do not change.
+assert.strictEqual(timing.startTime,initialTiming.startTime);
+assert.strictEqual(timing.nodeStart,initialTiming.nodeStart);
+assert.strictEqual(timing.v8Start,initialTiming.v8Start);
+assert.strictEqual(timing.environment,initialTiming.environment);
+assert.strictEqual(timing.bootstrapComplete,initialTiming.bootstrapComplete);
+
+assert.strictEqual(typeoftiming.loopStart,'number');
+assert.strictEqual(typeoftiming.loopExit,'number');
+}
+
+log('check initial nodeTiming');
+checkNodeTiming(initialTiming);
+assert.strictEqual(initialTiming.loopExit,-1);
 
-setTimeout(()=>{
-checkNodeTiming({
-name: 'node',
-entryType: 'node',
-startTime: 0,
-duration: {around: performance.now()},
-nodeStart: {around: 0},
-v8Start: {around: 0},
-bootstrapComplete: {around: inited,delay: 2500},
-environment: {around: 0},
-loopStart: {around: inited,delay: 2500},
-loopExit: -1
-});
-},1000);
+functioncheckValue(timing,name,min,max){
+constvalue=timing[name];
+assert(value>0,`${name}${value} <= 0`);
+// Loop starts after bootstrap completes.
+assert(value>min,
+`${name}${value} <= ${min}`);
+assert(value<max,`${name}${value} >= ${max}`);
+}
+
+letloopStart=initialTiming.loopStart;
+if(common.isMainThread){
+// In the main thread, the loop does not start until we start an operation
+// that requires it, e.g. setTimeout().
+assert.strictEqual(initialTiming.loopStart,-1);
+log('Start timer');
+setTimeout(()=>{
+log('Check nodeTiming in timer');
+consttiming={ ...performance.nodeTiming};
+checkNodeTiming(timing);
+// Loop should start after we fire the timeout, and before we call
+// performance.now() here.
+loopStart=timing.loopStart;
+checkValue(timing,'loopStart',initialTiming.duration,performance.now());
+},1000);
+}else{
+// In the worker, the loop always starts before the user code is evaluated,
+// and after bootstrap completes.
+checkValue(initialTiming,
+'loopStart',
+initialTiming.bootstrapComplete,
+testStartTime);
+}
 
 process.on('exit',()=>{
-checkNodeTiming({
-name: 'node',
-entryType: 'node',
-startTime: 0,
-duration: {around: performance.now()},
-nodeStart: {around: 0},
-v8Start: {around: 0},
-bootstrapComplete: {around: inited,delay: 2500},
-environment: {around: 0},
-loopStart: {around: inited,delay: 2500},
-loopExit: {around: performance.now()}
-});
+log('Check nodeTiming in process exit event');
+consttiming={ ...performance.nodeTiming};
+checkNodeTiming(timing);
+// Check that loopStart does not change.
+assert.strictEqual(timing.loopStart,loopStart);
+checkValue(timing,
+'loopExit',
+loopStart,
+performance.now());
 });