test: harden the tick sampling logic

HarshithaKP · addaleax · commit 73fec7cd00d6 · 2020-03-30T19:18:47.000+02:00
Under peculiar system load conditions, the profiler thread does not get enough CPU slices to perform the sampling. Improve the interaction between worker and parent thread by performing a large disc read, which is a better blend of CPU and I/O bound work, than earlier versions. This produces x10 more samples than the existing one, in 10 iterations, as opposed to 1024. Also capture worker error situations to improve debugging Refs: #26401 (comment) PR-URL: #32190 Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl> Reviewed-By: Anna Henningsen <anna@addaleax.net> Reviewed-By: James M Snell <jasnell@gmail.com>
diff --git a/test/sequential/test-worker-prof.js b/test/sequential/test-worker-prof.js
@@ -11,6 +11,7 @@ const { spawnSync } = require('child_process');
 // Refs: https://github.com/nodejs/node/issues/24016
 
 if (process.argv[2] === 'child') {
+  const fs = require('fs');
   let files = fs.readdirSync(tmpdir.path);
   const plog = files.filter((name) => /\.log$/.test(name))[0];
   if (plog === undefined) {
@@ -19,20 +20,20 @@ if (process.argv[2] === 'child') {
   }
   const pingpong = `
   let counter = 0;
+  const fs = require('fs');
   const { Worker, parentPort  } = require('worker_threads');
   parentPort.on('message', (m) => {
-    if (counter++ === 1024)
+    if (counter++ === 10)
       process.exit(0);
      parentPort.postMessage(
-       m.toString().split('').reverse().toString().replace(/,/g, ''));
+       fs.readFileSync(m.toString()).slice(0, 1024 * 1024));
   });
   `;
 
   const { Worker } = require('worker_threads');
-  const data = 'x'.repeat(1024);
   const w = new Worker(pingpong, { eval: true });
   w.on('message', (m) => {
-    w.postMessage(m.toString().split('').reverse().toString().replace(/,/g, ''));
+    w.postMessage(process.execPath);
   });
 
   w.on('exit', common.mustCall(() => {
@@ -45,7 +46,7 @@ if (process.argv[2] === 'child') {
     }
     process.exit(0);
   }));
-  w.postMessage(data);
+  w.postMessage(process.execPath);
 } else {
   tmpdir.refresh();
   const spawnResult = spawnSync(
