Collect timeout feature (#239)

cmd.js

@@ -60,6 +60,7 @@ async function cmd (argv, banner = defaultBanner) {
       visualizeOnly: 'visualize-only',
       visualizeCpuProfile: 'visualize-cpu-profile',
       collectOnly: 'collect-only',
+      collectDelay: 'collect-delay',
       kernelTracing: 'kernel-tracing',
       kernelTracingDebug: 'kernel-tracing-debug',
       treeDebug: 'tree-debug',

docs/api.md

@@ -59,6 +59,12 @@ with relevant outputs.
 
 Default: false
 
+#### `collectDelay` (number)
+
+Specify a delay(ms) before collecting data.
+
+Default: 0
+
 #### `mapFrames` (function)
 
 A custom mapping function that receives 

index.js

@@ -25,8 +25,10 @@ async function zeroEks (args) {
     args.pathToNodeBinary = pathTo('node')
   }
 
+  args.collectDelay = args.collectDelay || 0
+
   validate(args)
-  const { collectOnly, visualizeOnly, writeTicks, treeDebug, mapFrames, visualizeCpuProfile } = args
+  const { collectOnly, visualizeOnly, writeTicks, treeDebug, mapFrames, visualizeCpuProfile, collectDelay } = args
 
   let incompatibleOptions = 0
   if (collectOnly) incompatibleOptions += 1
@@ -63,6 +65,10 @@ async function zeroEks (args) {
     return folder
   }
 
+  if (collectDelay) {
+    debug('data collection will be delayed by ' + collectDelay + ' ms')
+  }
+
   try {
     const file = generateFlamegraph({ ...args, ticks, inlined, pid, folder })
     return file
@@ -145,7 +151,7 @@ async function visualize ({ visualizeOnly, treeDebug, workingDir, title, mapFram
     name = name || meta.name
 
     const ticks = (srcType === 'v8')
-      ? await v8LogToTicks(src, pathToNodeBinary)
+      ? await v8LogToTicks(src, { pathToNodeBinary })
       : traceStacksToTicks(src)
 
     if (treeDebug === true) {

lib/v8-log-to-ticks.js

@@ -15,9 +15,9 @@ const nodeMajorV = Number(process.versions.node.split('.')[0])
 
 module.exports = wrapper
 
-async function wrapper (isolateLogPath, node) {
+async function wrapper (isolateLogPath, options) {
   const normalised = await prepareForPreprocess(isolateLogPath)
-  return v8LogToTicks(normalised, node)
+  return v8LogToTicks(normalised, options)
 }
 
 // 1. Filter because long lines make the --preprocess crash. Filter them beforehand,
@@ -67,9 +67,9 @@ function fixLines (line) {
   }
 }
 
-function v8LogToTicks (isolateLogPath, node) {
+function v8LogToTicks (isolateLogPath, options) {
   const isJson = extname(isolateLogPath) === '.json'
-  const sp = isJson || spawn(node, [
+  const sp = isJson || spawn(options.pathToNodeBinary, [
     '--prof-process', '--preprocess', isolateLogPath
   ], { stdio: ['ignore', 'pipe', 'pipe'] })
 
@@ -119,10 +119,18 @@ function v8LogToTicks (isolateLogPath, node) {
       close()
     })
 
+    const firstTick = []
+    const delayMs = options.collectDelay * 1000;
     const tickStream = parse('ticks.*', (tick) => {
       const addr = tick.s.filter((n, i) => i % 2 === 0)
       var stack = addr.map((n) => codes[n]).filter(Boolean)
-      ticks.push(stack.reverse())
+      if (firstTick.length === 0) {
+        firstTick.push(tick.tm)
+      }
+      // Compare ticks to first for collectDelay
+      if (tick.tm > (firstTick[0] + delayMs)) {
+        ticks.push(stack.reverse())
+      }
     })
 
     pump(srcStream, tickStream, (err) => {

platform/v8.js

@@ -21,7 +21,7 @@ const {
 module.exports = v8
 
 async function v8 (args) {
-  const { status, outputDir, workingDir, name, onPort, pathToNodeBinary } = args
+  const { status, outputDir, workingDir, name, onPort, pathToNodeBinary, collectDelay } = args
 
   let proc = spawn(pathToNodeBinary, [
     '--prof',
@@ -114,7 +114,7 @@ async function v8 (args) {
   const isolateLogPath = path.join(folder, isolateLog)
   await renameSafe(path.join(args.workingDir, isolateLog), isolateLogPath)
   return {
-    ticks: await v8LogToTicks(isolateLogPath, pathToNodeBinary),
+    ticks: await v8LogToTicks(isolateLogPath, { pathToNodeBinary, collectDelay }),
     inlined: inlined,
     pid: proc.pid,
     folder: folder

readme.md

@@ -226,6 +226,12 @@ with relevant outputs.
 
 Default: false
 
+### --collect-delay
+
+Delay the collection of stacks by a specified time(ms) relative to the first entry.
+
+Default: 0
+
 ### --visualize-only
 
 Supply a path to a profile folder to build or rebuild visualization

schema.json

@@ -100,6 +100,12 @@
     },
     "P": {
       "type": "string"
+    },
+    "collect-delay": {
+      "type": "number"
+    },
+    "collectDelay": {
+      "type": "number"
     },
      "kernelTracing": {
       "type": "boolean"

usage.txt

@@ -66,6 +66,9 @@
 
   --collect-only          Do not process captured stacks into a flamegraph.
 
+  --collect-delay         Specify a delay(ms) before collecting data.
+
+
   --visualize-only <dir>  Build or rebuild flamegraph using the output dir.
                           Counterpart to --collect-only.