feat: use node histogram

Use Node standard library histogram. Closes #442.
dnlup · Nov 2, 2023 · eb20316 · eb20316
1 parent 60d6f09
commit eb20316
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Showing 4 changed files with 43 additions and 44 deletions.
diff --git a/lib/gc.js b/lib/gc.js
@@ -1,6 +1,6 @@
 'use strict'
 
-const { PerformanceObserver, constants } = require('perf_hooks')
+const { PerformanceObserver, constants, createHistogram } = require('perf_hooks')
 const {
   NODE_PERFORMANCE_GC_MAJOR,
   NODE_PERFORMANCE_GC_MINOR,
@@ -14,7 +14,6 @@ const {
   NODE_PERFORMANCE_GC_FLAGS_ALL_EXTERNAL_MEMORY,
   NODE_PERFORMANCE_GC_FLAGS_SCHEDULE_IDLE
 } = constants
-const hdr = require('hdr-histogram-js')
 const {
   kSample,
   kReset,
@@ -23,17 +22,13 @@ const {
   kStop
 } = require('./symbols')
 
-hdr.initWebAssemblySync()
-
 const kHistogram = Symbol('kHistogram')
 const kTotalDuration = Symbol('kTotalDuration')
 
 class GCEntry {
   constructor () {
-    this[kHistogram] = hdr.build({
-      useWebAssembly: true,
-      lowestDiscernibleValue: 1,
-      highestTrackableValue: 1e10
+    this[kHistogram] = createHistogram({
+      lowestDiscernibleValue: 1
     })
     this[kTotalDuration] = 0
   }
@@ -43,38 +38,37 @@ class GCEntry {
   }
 
   get totalCount () {
-    return this[kHistogram].totalCount
+    return this[kHistogram].count
   }
 
   get mean () {
     return this[kHistogram].mean
   }
 
   get max () {
-    return this[kHistogram].maxValue
+    return this[kHistogram].max
   }
 
-  // It seems this is not well supprted in hdr-histogram
-  // See https://github.com/HdrHistogram/HdrHistogramJS/issues/11
   get min () {
-    return this[kHistogram].minNonZeroValue
+    return this[kHistogram].min
   }
 
   get stdDeviation () {
-    return this[kHistogram].stdDeviation
-  }
-
-  get summary () {
-    return this[kHistogram].summary
+    return this[kHistogram].stddev
   }
 
   getPercentile (percentile) {
-    return this[kHistogram].getValueAtPercentile(percentile)
+    return this[kHistogram].percentile(percentile)
   }
 
   [kSample] (ns) {
     this[kTotalDuration] += ns
-    this[kHistogram].recordValue(ns)
+    /**
+     * We have to truncate the value here because `record`
+     * only accepts integer values:
+     * https://github.com/nodejs/node/blob/cdad3d8fe5f468aec6549fd59db73a3bfe063e3c/lib/internal/histogram.js#L283-L284
+     */
+    this[kHistogram].record(Math.trunc(ns))
   }
 
   [kReset] () {

diff --git a/package.json b/package.json
@@ -91,7 +91,6 @@
     "typescript": "^5.2.2"
   },
   "dependencies": {
-    "@dnlup/hrtime-utils": "^1.1.0",
-    "hdr-histogram-js": "^3.0.0"
+    "@dnlup/hrtime-utils": "^1.1.0"
   }
 }
diff --git a/test/doc.test.js b/test/doc.test.js
@@ -160,7 +160,7 @@ test('eventLoopUtilization', { skip: !doc.eventLoopUtilizationSupported }, t =>
   })
 })
 
-test('gc', t => {
+test('gc', { only: true }, t => {
   t.plan(25)
   const sampler = doc({
     gcOptions: {
@@ -184,7 +184,7 @@ test('gc', t => {
   })
 })
 
-test('gc aggregation with flags', { skip: !doc.gcFlagsSupported }, t => {
+test('gc aggregation with flags', t => {
   t.plan(145)
   const sampler = doc({
     gcOptions: {
@@ -223,7 +223,7 @@ test('gc aggregation with flags', { skip: !doc.gcFlagsSupported }, t => {
   })
 })
 
-test('resourceUsage', { skip: !doc.resourceUsageSupported }, t => {
+test('resourceUsage', t => {
   const sampler = doc({ collect: { resourceUsage: true } })
   preventTestExitingEarly(t, 2000)
   sampler.once('sample', () => {

diff --git a/test/gc.test.js b/test/gc.test.js
@@ -11,7 +11,6 @@ const {
   kReset,
   kObserverCallback
 } = require('../lib/symbols')
-const { gcFlagsSupported } = require('../lib/util')
 
 test('garbage collection metric without aggregation', t => {
   const data = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
@@ -46,11 +45,10 @@ test('garbage collection metric without aggregation', t => {
   t.ok(gc.pause instanceof GCEntry)
   t.equal(gc.pause.totalCount, 4 * data.length)
   t.equal(gc.pause.totalDuration, 4 * entryDurationSum * 1e6)
-  t.equal(gc.pause.max, 10 * 1e6)
-  t.equal(gc.pause.min, 1 * 1e6)
+  t.equal(gc.pause.max, 10002431)
+  t.equal(gc.pause.min, 999936)
   t.ok(gc.pause.mean > approxMean)
   t.ok(gc.pause.getPercentile(99) > 10 * 1e6)
-  t.ok(typeof gc.pause.summary === 'object')
   t.ok(gc.pause.stdDeviation > 0)
 
   // Check it resets correctly
@@ -59,8 +57,6 @@ test('garbage collection metric without aggregation', t => {
   t.equal(gc.pause.totalDuration, 0)
   t.equal(gc.pause.max, 0)
   // Not testing min value because it looks like is not initialized to zero.
-  // A possible discussion to follow:
-  // * https://github.com/HdrHistogram/HdrHistogramJS/issues/11
   // t.equal(gc.pause.min, 0)
   t.equal(gc.pause.getPercentile(99), 0)
   t.end()
@@ -101,11 +97,10 @@ test('garbage collection metric with aggregation', t => {
   t.ok(gc.pause instanceof GCEntry)
   t.equal(gc.pause.totalCount, 4 * data.length)
   t.equal(gc.pause.totalDuration, 4 * entryDurationSum * 1e6)
-  t.equal(gc.pause.max, 10 * 1e6)
-  t.equal(gc.pause.min, 1 * 1e6)
+  t.equal(gc.pause.max, 10002431)
+  t.equal(gc.pause.min, 999936)
   t.ok(gc.pause.mean > approxMean)
   t.ok(gc.pause.getPercentile(99) > 10 * 1e6)
-  t.ok(typeof gc.pause.summary === 'object')
   t.ok(gc.pause.stdDeviation > 0)
 
   for (const entry of [
@@ -138,15 +133,15 @@ test('garbage collection metric with aggregation', t => {
     'weakCb'
   ]) {
     const errorMessage = `Failed check for entry ${entry}`
-    t.equal(gc[entry].mean, 0, errorMessage)
+    t.ok(isNaN(gc[entry].mean), errorMessage)
     t.equal(gc[entry].totalCount, 0, errorMessage)
     t.ok(gc[entry].flags === undefined)
   }
 
   t.end()
 })
 
-test('garbage collection metric with aggregation and flags', { skip: !gcFlagsSupported }, t => {
+test('garbage collection metric with aggregation and flags', t => {
   const data = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
 
   // Creates a fake list that's the same shape as PerformanceObserver
@@ -183,11 +178,10 @@ test('garbage collection metric with aggregation and flags', { skip: !gcFlagsSup
   t.ok(gc.pause instanceof GCEntry)
   t.equal(gc.pause.totalCount, 4 * data.length)
   t.equal(gc.pause.totalDuration, 4 * entryDurationSum * 1e6)
-  t.equal(gc.pause.max, 10 * 1e6)
-  t.equal(gc.pause.min, 1 * 1e6)
+  t.equal(gc.pause.max, 10002431)
+  t.equal(gc.pause.min, 999936)
   t.ok(gc.pause.mean > approxMean)
   t.ok(gc.pause.getPercentile(99) > 10 * 1e6)
-  t.ok(typeof gc.pause.summary === 'object')
   t.ok(gc.pause.stdDeviation > 0)
 
   for (const entry of [
@@ -234,7 +228,14 @@ test('garbage collection metric with aggregation and flags', { skip: !gcFlagsSup
         'totalDuration'
       ]) {
         const errorMessage = `Failed check for ${entry}.flags.${flag}.${value}`
-        t.ok(gc.major.flags[flag][value] === 0, errorMessage)
+        switch (value) {
+          case 'mean':
+          case 'stdDeviation':
+            t.ok(isNaN(gc.major.flags[flag][value]), errorMessage)
+            break
+          default:
+            t.ok(gc.major.flags[flag][value] === 0, errorMessage)
+        }
       }
     }
   }
@@ -257,7 +258,7 @@ test('garbage collection metric with aggregation and flags', { skip: !gcFlagsSup
     'weakCb'
   ]) {
     const errorMessage = `Failed check for entry ${entry}`
-    t.equal(gc[entry].mean, 0, errorMessage)
+    t.ok(isNaN(gc[entry].mean), errorMessage)
     t.equal(gc[entry].totalCount, 0, errorMessage)
     t.ok(gc.major.flags.no instanceof GCEntry)
     t.equal(gc.major.flags.no.getPercentile(99), 0, errorMessage)
@@ -275,15 +276,20 @@ test('garbage collection metric with aggregation and flags', { skip: !gcFlagsSup
         'mean',
         'max',
         // Not testing min value because it looks like is not initialized to zero.
-        // A possible discussion to follow:
-        // * https://github.com/HdrHistogram/HdrHistogramJS/issues/11
         // 'min',
         'stdDeviation',
         'totalCount',
         'totalDuration'
       ]) {
         const errorMessage = `Failed check for ${entry}.flags.${flag}.${value}`
-        t.ok(gc.major.flags[flag][value] === 0, errorMessage)
+        switch (value) {
+          case 'mean':
+          case 'stdDeviation':
+            t.ok(isNaN(gc.major.flags[flag][value]), errorMessage)
+            break
+          default:
+            t.ok(gc.major.flags[flag][value] === 0, errorMessage)
+        }
       }
     }
   }