From 95d36a386c2d44dba558a6ed2373d3021af9b7b7 Mon Sep 17 00:00:00 2001
From: RafaelGSS <rafael.nunu@hotmail.com>
Date: Fri, 16 Aug 2024 17:14:27 -0300
Subject: [PATCH 1/9] src,lib: add performance.uvMetricsInfo

This commit exposes a new API to the perf_hooks.performance
module. This wraps uv_metrics_info into
performance.uvMetricsInfo() function.
---
 doc/api/perf_hooks.md                         | 25 +++++++
 lib/internal/perf/performance.js              | 11 +++
 lib/internal/perf/uv_metrics.js               | 11 +++
 src/env_properties.h                          |  3 +
 src/node_perf.cc                              | 26 +++++++
 .../test-performance-uvmetricsinfo.js         | 74 +++++++++++++++++++
 6 files changed, 150 insertions(+)
 create mode 100644 lib/internal/perf/uv_metrics.js
 create mode 100644 test/parallel/test-performance-uvmetricsinfo.js

diff --git a/doc/api/perf_hooks.md b/doc/api/perf_hooks.md
index 298d1a94330d65..351a4fdc9a3875 100644
--- a/doc/api/perf_hooks.md
+++ b/doc/api/perf_hooks.md
@@ -444,6 +444,31 @@ If the wrapped function returns a promise, a finally handler will be attached
 to the promise and the duration will be reported once the finally handler is
 invoked.
 
+### `performance.uvMetricsInfo()`
+
+<!-- YAML
+added: REPLACEME
+-->
+
+* Returns: {Object}
+  * `loopCount` {number} Number of event loop iterations.
+  * `events` {number} Number of events that have been processed by the event handler.
+  * `events_waiting` {number} Number of events that were waiting to be processed when the event provider was called.
+
+This is an wrapper to the `uv_metrics_info`.
+It returns the current set of event loop metrics.
+
+It's recommended to use this function inside a `setImmediate` to avoid
+collecting metrics before finishing all operations on current loop iteration.
+
+```js
+const { performance } = require('node:perf_hooks');
+
+setImmediate(() => {
+  console.log(performance.uvMetricsInfo());
+});
+```
+
 ### `performance.toJSON()`
 
 <!-- YAML
diff --git a/lib/internal/perf/performance.js b/lib/internal/perf/performance.js
index 836dcaa87d8b31..da150eb97fabda 100644
--- a/lib/internal/perf/performance.js
+++ b/lib/internal/perf/performance.js
@@ -39,6 +39,7 @@ const {
 } = require('internal/perf/observe');
 
 const { eventLoopUtilization } = require('internal/perf/event_loop_utilization');
+const { uvMetricsInfo } = require('internal/perf/uv_metrics');
 const nodeTiming = require('internal/perf/nodetiming');
 const timerify = require('internal/perf/timerify');
 const { customInspectSymbol: kInspect, kEnumerableProperty, kEmptyObject } = require('internal/util');
@@ -157,6 +158,7 @@ class Performance extends EventTarget {
       nodeTiming: this.nodeTiming,
       timeOrigin: this.timeOrigin,
       eventLoopUtilization: this.eventLoopUtilization(),
+      uvMetrics: this.uvMetricsInfo(),
     };
   }
 }
@@ -191,6 +193,15 @@ ObjectDefineProperties(Performance.prototype, {
     writable: true,
     value: eventLoopUtilization,
   },
+  uvMetricsInfo: {
+    __proto__: null,
+    configurable: true,
+    // Node.js specific extensions.
+    enumerable: false,
+    writable: true,
+    value: uvMetricsInfo,
+  },
+
   nodeTiming: {
     __proto__: null,
     configurable: true,
diff --git a/lib/internal/perf/uv_metrics.js b/lib/internal/perf/uv_metrics.js
new file mode 100644
index 00000000000000..c5f4056f4de7b1
--- /dev/null
+++ b/lib/internal/perf/uv_metrics.js
@@ -0,0 +1,11 @@
+'use strict';
+
+const binding = internalBinding('performance');
+
+function uvMetricsInfo() {
+  return binding.uvMetricsInfo();
+}
+
+module.exports = {
+  uvMetricsInfo,
+};
diff --git a/src/env_properties.h b/src/env_properties.h
index 1ed8ab4d116313..6f986360b29463 100644
--- a/src/env_properties.h
+++ b/src/env_properties.h
@@ -143,6 +143,8 @@
   V(env_var_settings_string, "envVarSettings")                                 \
   V(errno_string, "errno")                                                     \
   V(error_string, "error")                                                     \
+  V(events, "events")                                                          \
+  V(events_waiting, "events_waiting")                                          \
   V(exchange_string, "exchange")                                               \
   V(expire_string, "expire")                                                   \
   V(exponent_string, "exponent")                                               \
@@ -212,6 +214,7 @@
   V(kind_string, "kind")                                                       \
   V(length_string, "length")                                                   \
   V(library_string, "library")                                                 \
+  V(loop_count, "loop_count")                                                  \
   V(mac_string, "mac")                                                         \
   V(max_buffer_string, "maxBuffer")                                            \
   V(max_concurrent_streams_string, "maxConcurrentStreams")                     \
diff --git a/src/node_perf.cc b/src/node_perf.cc
index 1aa264cc1e64ad..a95f81929fc17d 100644
--- a/src/node_perf.cc
+++ b/src/node_perf.cc
@@ -261,6 +261,30 @@ void LoopIdleTime(const FunctionCallbackInfo<Value>& args) {
   args.GetReturnValue().Set(1.0 * idle_time / NANOS_PER_MILLIS);
 }
 
+void UvMetricsInfo(const FunctionCallbackInfo<Value>& args) {
+  Environment* env = Environment::GetCurrent(args);
+  uv_metrics_t metrics;
+
+  // uv_metrics_info always return 0
+  uv_metrics_info(env->event_loop(), &metrics);
+
+  Local<Object> obj = Object::New(env->isolate());
+  obj->Set(env->context(),
+           env->loop_count(),
+           Integer::NewFromUnsigned(env->isolate(), metrics.loop_count))
+      .Check();
+  obj->Set(env->context(),
+           env->events(),
+           Integer::NewFromUnsigned(env->isolate(), metrics.events))
+      .Check();
+  obj->Set(env->context(),
+           env->events_waiting(),
+           Integer::NewFromUnsigned(env->isolate(), metrics.events_waiting))
+      .Check();
+
+  args.GetReturnValue().Set(obj);
+}
+
 void CreateELDHistogram(const FunctionCallbackInfo<Value>& args) {
   Environment* env = Environment::GetCurrent(args);
   int64_t interval = args[0].As<Integer>()->Value();
@@ -324,6 +348,7 @@ static void CreatePerIsolateProperties(IsolateData* isolate_data,
   SetMethod(isolate, target, "loopIdleTime", LoopIdleTime);
   SetMethod(isolate, target, "createELDHistogram", CreateELDHistogram);
   SetMethod(isolate, target, "markBootstrapComplete", MarkBootstrapComplete);
+  SetMethod(isolate, target, "uvMetricsInfo", UvMetricsInfo);
   SetFastMethodNoSideEffect(
       isolate, target, "now", SlowPerformanceNow, &fast_performance_now);
 }
@@ -390,6 +415,7 @@ void RegisterExternalReferences(ExternalReferenceRegistry* registry) {
   registry->Register(LoopIdleTime);
   registry->Register(CreateELDHistogram);
   registry->Register(MarkBootstrapComplete);
+  registry->Register(UvMetricsInfo);
   registry->Register(SlowPerformanceNow);
   registry->Register(FastPerformanceNow);
   registry->Register(fast_performance_now.GetTypeInfo());
diff --git a/test/parallel/test-performance-uvmetricsinfo.js b/test/parallel/test-performance-uvmetricsinfo.js
new file mode 100644
index 00000000000000..b03d9c9df40473
--- /dev/null
+++ b/test/parallel/test-performance-uvmetricsinfo.js
@@ -0,0 +1,74 @@
+'use strict';
+
+require('../common');
+
+const fixtures = require('../common/fixtures');
+
+const filepath = fixtures.path('x.txt');
+
+const assert = require('node:assert');
+const fs = require('node:fs');
+const { performance } = require('node:perf_hooks');
+
+const { uvMetricsInfo } = performance;
+
+function safeMetricsInfo(cb) {
+  setImmediate(() => {
+    const info = uvMetricsInfo();
+    cb(info);
+  });
+}
+
+{
+  const info = uvMetricsInfo();
+  assert.strictEqual(info.loop_count, 0);
+  assert.strictEqual(info.events, 0);
+  // This is the only part of the test that we test events waiting
+  // Adding checks for this property will make the test flaky
+  // as it can be highly influenced by race conditions.
+  assert.strictEqual(info.events_waiting, 0);
+}
+
+{
+  // The synchronous call should obviously not affect the uv metrics
+  const fd = fs.openSync(filepath, 'r');
+  fs.readFileSync(fd);
+  const info = uvMetricsInfo();
+  assert.strictEqual(info.loop_count, 0);
+  assert.strictEqual(info.events, 0);
+  assert.strictEqual(info.events_waiting, 0);
+}
+
+{
+  function openFile(info) {
+    assert.strictEqual(info.loop_count, 1);
+    // 1. ? event
+    assert.strictEqual(info.events, 1);
+
+    fs.open(filepath, 'r', (err) => {
+      assert.ifError(err);
+      safeMetricsInfo(afterOpenFile);
+    });
+  }
+
+  function afterOpenFile(info) {
+    assert.strictEqual(info.loop_count, 2);
+    // 1. ? event
+    // 2. uv_fs_open
+    assert.strictEqual(info.events, 2);
+
+    fs.readFile(filepath, (err) => {
+      assert.ifError(err);
+      safeMetricsInfo(afterReadFile);
+    });
+  }
+
+  function afterReadFile(info) {
+    assert.strictEqual(info.loop_count, 6);
+    // 1. ? event
+    assert.strictEqual(info.events, 6);
+    // 1. ?
+  }
+
+  safeMetricsInfo(openFile);
+}

From 1861bb21943fdb24b9233f558892d29a1b50e709 Mon Sep 17 00:00:00 2001
From: RafaelGSS <rafael.nunu@hotmail.com>
Date: Fri, 16 Aug 2024 17:47:53 -0300
Subject: [PATCH 2/9] fixup! src,lib: add performance.uvMetricsInfo

---
 doc/api/perf_hooks.md                           |  2 +-
 src/env_properties.h                            |  4 ++--
 test/parallel/test-performance-uvmetricsinfo.js | 14 +++++++-------
 3 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/doc/api/perf_hooks.md b/doc/api/perf_hooks.md
index 351a4fdc9a3875..be068613b3c841 100644
--- a/doc/api/perf_hooks.md
+++ b/doc/api/perf_hooks.md
@@ -453,7 +453,7 @@ added: REPLACEME
 * Returns: {Object}
   * `loopCount` {number} Number of event loop iterations.
   * `events` {number} Number of events that have been processed by the event handler.
-  * `events_waiting` {number} Number of events that were waiting to be processed when the event provider was called.
+  * `eventsWaiting` {number} Number of events that were waiting to be processed when the event provider was called.
 
 This is an wrapper to the `uv_metrics_info`.
 It returns the current set of event loop metrics.
diff --git a/src/env_properties.h b/src/env_properties.h
index 6f986360b29463..f54648b461e955 100644
--- a/src/env_properties.h
+++ b/src/env_properties.h
@@ -144,7 +144,7 @@
   V(errno_string, "errno")                                                     \
   V(error_string, "error")                                                     \
   V(events, "events")                                                          \
-  V(events_waiting, "events_waiting")                                          \
+  V(events_waiting, "eventsWaiting")                                           \
   V(exchange_string, "exchange")                                               \
   V(expire_string, "expire")                                                   \
   V(exponent_string, "exponent")                                               \
@@ -214,7 +214,7 @@
   V(kind_string, "kind")                                                       \
   V(length_string, "length")                                                   \
   V(library_string, "library")                                                 \
-  V(loop_count, "loop_count")                                                  \
+  V(loop_count, "loopCount")                                                   \
   V(mac_string, "mac")                                                         \
   V(max_buffer_string, "maxBuffer")                                            \
   V(max_concurrent_streams_string, "maxConcurrentStreams")                     \
diff --git a/test/parallel/test-performance-uvmetricsinfo.js b/test/parallel/test-performance-uvmetricsinfo.js
index b03d9c9df40473..1e63ca34a5ea75 100644
--- a/test/parallel/test-performance-uvmetricsinfo.js
+++ b/test/parallel/test-performance-uvmetricsinfo.js
@@ -21,12 +21,12 @@ function safeMetricsInfo(cb) {
 
 {
   const info = uvMetricsInfo();
-  assert.strictEqual(info.loop_count, 0);
+  assert.strictEqual(info.loopCount, 0);
   assert.strictEqual(info.events, 0);
   // This is the only part of the test that we test events waiting
   // Adding checks for this property will make the test flaky
   // as it can be highly influenced by race conditions.
-  assert.strictEqual(info.events_waiting, 0);
+  assert.strictEqual(info.eventsWaiting, 0);
 }
 
 {
@@ -34,14 +34,14 @@ function safeMetricsInfo(cb) {
   const fd = fs.openSync(filepath, 'r');
   fs.readFileSync(fd);
   const info = uvMetricsInfo();
-  assert.strictEqual(info.loop_count, 0);
+  assert.strictEqual(info.loopCount, 0);
   assert.strictEqual(info.events, 0);
-  assert.strictEqual(info.events_waiting, 0);
+  assert.strictEqual(info.eventsWaiting, 0);
 }
 
 {
   function openFile(info) {
-    assert.strictEqual(info.loop_count, 1);
+    assert.strictEqual(info.loopCount, 1);
     // 1. ? event
     assert.strictEqual(info.events, 1);
 
@@ -52,7 +52,7 @@ function safeMetricsInfo(cb) {
   }
 
   function afterOpenFile(info) {
-    assert.strictEqual(info.loop_count, 2);
+    assert.strictEqual(info.loopCount, 2);
     // 1. ? event
     // 2. uv_fs_open
     assert.strictEqual(info.events, 2);
@@ -64,7 +64,7 @@ function safeMetricsInfo(cb) {
   }
 
   function afterReadFile(info) {
-    assert.strictEqual(info.loop_count, 6);
+    assert.strictEqual(info.loopCount, 6);
     // 1. ? event
     assert.strictEqual(info.events, 6);
     // 1. ?

From 85dbd8f5621fef9b6c460c3423d6848fa36fdca3 Mon Sep 17 00:00:00 2001
From: RafaelGSS <rafael.nunu@hotmail.com>
Date: Fri, 16 Aug 2024 17:48:40 -0300
Subject: [PATCH 3/9] fixup! add mjs doc

---
 doc/api/perf_hooks.md | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/doc/api/perf_hooks.md b/doc/api/perf_hooks.md
index be068613b3c841..e5fa7040bf2c24 100644
--- a/doc/api/perf_hooks.md
+++ b/doc/api/perf_hooks.md
@@ -461,7 +461,7 @@ It returns the current set of event loop metrics.
 It's recommended to use this function inside a `setImmediate` to avoid
 collecting metrics before finishing all operations on current loop iteration.
 
-```js
+```cjs
 const { performance } = require('node:perf_hooks');
 
 setImmediate(() => {
@@ -469,6 +469,14 @@ setImmediate(() => {
 });
 ```
 
+```mjs
+import { performance } from 'node:perf_hooks';
+
+setImmediate(() => {
+  console.log(performance.uvMetricsInfo());
+});
+```
+
 ### `performance.toJSON()`
 
 <!-- YAML

From aa4dc99d91a6a37cc4fbadcc681c21ef7ef31ee8 Mon Sep 17 00:00:00 2001
From: Rafael Gonzaga <rafael.nunu@hotmail.com>
Date: Sat, 17 Aug 2024 10:30:11 -0300
Subject: [PATCH 4/9] fixup! apply cr suggestions
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Co-authored-by: Tobias Nießen <tniessen@tnie.de>
---
 doc/api/perf_hooks.md | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/doc/api/perf_hooks.md b/doc/api/perf_hooks.md
index e5fa7040bf2c24..779469f5ee7300 100644
--- a/doc/api/perf_hooks.md
+++ b/doc/api/perf_hooks.md
@@ -455,11 +455,12 @@ added: REPLACEME
   * `events` {number} Number of events that have been processed by the event handler.
   * `eventsWaiting` {number} Number of events that were waiting to be processed when the event provider was called.
 
-This is an wrapper to the `uv_metrics_info`.
+This is a wrapper to the `uv_metrics_info` function.
 It returns the current set of event loop metrics.
 
-It's recommended to use this function inside a `setImmediate` to avoid
-collecting metrics before finishing all operations on current loop iteration.
+It is recommended to use this function inside a function whose execution was
+scheduled using `setImmediate` to avoid collecting metrics before finishing all
+operations scheduled during the current loop iteration.
 
 ```cjs
 const { performance } = require('node:perf_hooks');

From c1385edaa52a0726f5ab844a9a33b332bf40215d Mon Sep 17 00:00:00 2001
From: RafaelGSS <rafael.nunu@hotmail.com>
Date: Tue, 20 Aug 2024 13:35:24 -0300
Subject: [PATCH 5/9] fixup! use performance.nodeTiming instead

---
 lib/internal/perf/nodetiming.js                       |  8 ++++++++
 lib/internal/perf/performance.js                      | 10 ----------
 lib/internal/perf/uv_metrics.js                       | 11 -----------
 ...s => test-performance-nodetiming-uvmetricsinfo.js} |  8 ++++----
 4 files changed, 12 insertions(+), 25 deletions(-)
 delete mode 100644 lib/internal/perf/uv_metrics.js
 rename test/parallel/{test-performance-uvmetricsinfo.js => test-performance-nodetiming-uvmetricsinfo.js} (90%)

diff --git a/lib/internal/perf/nodetiming.js b/lib/internal/perf/nodetiming.js
index 11f877e5d81b44..d19bc021263a7f 100644
--- a/lib/internal/perf/nodetiming.js
+++ b/lib/internal/perf/nodetiming.js
@@ -28,6 +28,7 @@ const {
     NODE_PERFORMANCE_MILESTONE_ENVIRONMENT,
   },
   loopIdleTime,
+  uvMetricsInfo,
 } = internalBinding('performance');
 
 class PerformanceNodeTiming {
@@ -122,6 +123,13 @@ class PerformanceNodeTiming {
         configurable: true,
         get: loopIdleTime,
       },
+
+      uvMetricsInfo: {
+        __proto__: null,
+        enumerable: true,
+        configurable: true,
+        get: uvMetricsInfo,
+      },
     });
   }
 
diff --git a/lib/internal/perf/performance.js b/lib/internal/perf/performance.js
index da150eb97fabda..374e85898b6be7 100644
--- a/lib/internal/perf/performance.js
+++ b/lib/internal/perf/performance.js
@@ -39,7 +39,6 @@ const {
 } = require('internal/perf/observe');
 
 const { eventLoopUtilization } = require('internal/perf/event_loop_utilization');
-const { uvMetricsInfo } = require('internal/perf/uv_metrics');
 const nodeTiming = require('internal/perf/nodetiming');
 const timerify = require('internal/perf/timerify');
 const { customInspectSymbol: kInspect, kEnumerableProperty, kEmptyObject } = require('internal/util');
@@ -158,7 +157,6 @@ class Performance extends EventTarget {
       nodeTiming: this.nodeTiming,
       timeOrigin: this.timeOrigin,
       eventLoopUtilization: this.eventLoopUtilization(),
-      uvMetrics: this.uvMetricsInfo(),
     };
   }
 }
@@ -193,14 +191,6 @@ ObjectDefineProperties(Performance.prototype, {
     writable: true,
     value: eventLoopUtilization,
   },
-  uvMetricsInfo: {
-    __proto__: null,
-    configurable: true,
-    // Node.js specific extensions.
-    enumerable: false,
-    writable: true,
-    value: uvMetricsInfo,
-  },
 
   nodeTiming: {
     __proto__: null,
diff --git a/lib/internal/perf/uv_metrics.js b/lib/internal/perf/uv_metrics.js
deleted file mode 100644
index c5f4056f4de7b1..00000000000000
--- a/lib/internal/perf/uv_metrics.js
+++ /dev/null
@@ -1,11 +0,0 @@
-'use strict';
-
-const binding = internalBinding('performance');
-
-function uvMetricsInfo() {
-  return binding.uvMetricsInfo();
-}
-
-module.exports = {
-  uvMetricsInfo,
-};
diff --git a/test/parallel/test-performance-uvmetricsinfo.js b/test/parallel/test-performance-nodetiming-uvmetricsinfo.js
similarity index 90%
rename from test/parallel/test-performance-uvmetricsinfo.js
rename to test/parallel/test-performance-nodetiming-uvmetricsinfo.js
index 1e63ca34a5ea75..bdab0925dbce4c 100644
--- a/test/parallel/test-performance-uvmetricsinfo.js
+++ b/test/parallel/test-performance-nodetiming-uvmetricsinfo.js
@@ -10,17 +10,17 @@ const assert = require('node:assert');
 const fs = require('node:fs');
 const { performance } = require('node:perf_hooks');
 
-const { uvMetricsInfo } = performance;
+const { nodeTiming } = performance;
 
 function safeMetricsInfo(cb) {
   setImmediate(() => {
-    const info = uvMetricsInfo();
+    const info = nodeTiming.uvMetricsInfo;
     cb(info);
   });
 }
 
 {
-  const info = uvMetricsInfo();
+  const info = nodeTiming.uvMetricsInfo;
   assert.strictEqual(info.loopCount, 0);
   assert.strictEqual(info.events, 0);
   // This is the only part of the test that we test events waiting
@@ -33,7 +33,7 @@ function safeMetricsInfo(cb) {
   // The synchronous call should obviously not affect the uv metrics
   const fd = fs.openSync(filepath, 'r');
   fs.readFileSync(fd);
-  const info = uvMetricsInfo();
+  const info = nodeTiming.uvMetricsInfo;
   assert.strictEqual(info.loopCount, 0);
   assert.strictEqual(info.events, 0);
   assert.strictEqual(info.eventsWaiting, 0);

From 856d4ae079438a33d1820c541133a5b3be7bca0a Mon Sep 17 00:00:00 2001
From: RafaelGSS <rafael.nunu@hotmail.com>
Date: Wed, 21 Aug 2024 16:14:22 -0300
Subject: [PATCH 6/9] fixup! fixup! use performance.nodeTiming instead

---
 doc/api/perf_hooks.md            | 68 ++++++++++++++++----------------
 lib/internal/perf/performance.js |  1 -
 src/node_perf.cc                 |  2 +-
 3 files changed, 35 insertions(+), 36 deletions(-)

diff --git a/doc/api/perf_hooks.md b/doc/api/perf_hooks.md
index 779469f5ee7300..1623d9333fbca7 100644
--- a/doc/api/perf_hooks.md
+++ b/doc/api/perf_hooks.md
@@ -444,40 +444,6 @@ If the wrapped function returns a promise, a finally handler will be attached
 to the promise and the duration will be reported once the finally handler is
 invoked.
 
-### `performance.uvMetricsInfo()`
-
-<!-- YAML
-added: REPLACEME
--->
-
-* Returns: {Object}
-  * `loopCount` {number} Number of event loop iterations.
-  * `events` {number} Number of events that have been processed by the event handler.
-  * `eventsWaiting` {number} Number of events that were waiting to be processed when the event provider was called.
-
-This is a wrapper to the `uv_metrics_info` function.
-It returns the current set of event loop metrics.
-
-It is recommended to use this function inside a function whose execution was
-scheduled using `setImmediate` to avoid collecting metrics before finishing all
-operations scheduled during the current loop iteration.
-
-```cjs
-const { performance } = require('node:perf_hooks');
-
-setImmediate(() => {
-  console.log(performance.uvMetricsInfo());
-});
-```
-
-```mjs
-import { performance } from 'node:perf_hooks';
-
-setImmediate(() => {
-  console.log(performance.uvMetricsInfo());
-});
-```
-
 ### `performance.toJSON()`
 
 <!-- YAML
@@ -918,6 +884,40 @@ added: v8.5.0
 The high resolution millisecond timestamp at which the Node.js process was
 initialized.
 
+### `performanceNodeTiming.uvMetricsInfo`
+
+<!-- YAML
+added: REPLACEME
+-->
+
+* Returns: {Object}
+  * `loopCount` {number} Number of event loop iterations.
+  * `events` {number} Number of events that have been processed by the event handler.
+  * `eventsWaiting` {number} Number of events that were waiting to be processed when the event provider was called.
+
+This is a wrapper to the `uv_metrics_info` function.
+It returns the current set of event loop metrics.
+
+It is recommended to use this property inside a function whose execution was
+scheduled using `setImmediate` to avoid collecting metrics before finishing all
+operations scheduled during the current loop iteration.
+
+```cjs
+const { performance } = require('node:perf_hooks');
+
+setImmediate(() => {
+  console.log(performance.nodeTiming.uvMetricsInfo);
+});
+```
+
+```mjs
+import { performance } from 'node:perf_hooks';
+
+setImmediate(() => {
+  console.log(performance.nodeTiming.uvMetricsInfo);
+});
+```
+
 ### `performanceNodeTiming.v8Start`
 
 <!-- YAML
diff --git a/lib/internal/perf/performance.js b/lib/internal/perf/performance.js
index 374e85898b6be7..836dcaa87d8b31 100644
--- a/lib/internal/perf/performance.js
+++ b/lib/internal/perf/performance.js
@@ -191,7 +191,6 @@ ObjectDefineProperties(Performance.prototype, {
     writable: true,
     value: eventLoopUtilization,
   },
-
   nodeTiming: {
     __proto__: null,
     configurable: true,
diff --git a/src/node_perf.cc b/src/node_perf.cc
index a95f81929fc17d..a22eaf1a6f23c5 100644
--- a/src/node_perf.cc
+++ b/src/node_perf.cc
@@ -266,7 +266,7 @@ void UvMetricsInfo(const FunctionCallbackInfo<Value>& args) {
   uv_metrics_t metrics;
 
   // uv_metrics_info always return 0
-  uv_metrics_info(env->event_loop(), &metrics);
+  CHECK_EQ(uv_metrics_info(env->event_loop(), &metrics), 0);
 
   Local<Object> obj = Object::New(env->isolate());
   obj->Set(env->context(),

From 13fe044ebd15a1075da3b6314cc1a30c6bee5f3a Mon Sep 17 00:00:00 2001
From: RafaelGSS <rafael.nunu@hotmail.com>
Date: Mon, 26 Aug 2024 18:27:48 -0300
Subject: [PATCH 7/9] fixup! fixup! fixup! use performance.nodeTiming instead

---
 .../fixtures/test-nodetiming-uvmetricsinfo.js | 65 ++++++++++++++++
 ...st-performance-nodetiming-uvmetricsinfo.js | 78 +++----------------
 2 files changed, 77 insertions(+), 66 deletions(-)
 create mode 100644 test/fixtures/test-nodetiming-uvmetricsinfo.js

diff --git a/test/fixtures/test-nodetiming-uvmetricsinfo.js b/test/fixtures/test-nodetiming-uvmetricsinfo.js
new file mode 100644
index 00000000000000..484070103f6e05
--- /dev/null
+++ b/test/fixtures/test-nodetiming-uvmetricsinfo.js
@@ -0,0 +1,65 @@
+const { performance } = require('node:perf_hooks');
+const assert = require('node:assert');
+const fs = require('node:fs');
+const { nodeTiming } = performance;
+
+function safeMetricsInfo(cb) {
+  setImmediate(() => {
+    const info = nodeTiming.uvMetricsInfo;
+    cb(info);
+  });
+}
+
+{
+  const info = nodeTiming.uvMetricsInfo;
+  assert.strictEqual(info.loopCount, 0);
+  assert.strictEqual(info.events, 0);
+  // This is the only part of the test that we test events waiting
+  // Adding checks for this property will make the test flaky
+  // as it can be highly influenced by race conditions.
+  assert.strictEqual(info.eventsWaiting, 0);
+}
+
+{
+  // The synchronous call should obviously not affect the uv metrics
+  const fd = fs.openSync(__filename, 'r');
+  fs.readFileSync(fd);
+  const info = nodeTiming.uvMetricsInfo;
+  assert.strictEqual(info.loopCount, 0);
+  assert.strictEqual(info.events, 0);
+  assert.strictEqual(info.eventsWaiting, 0);
+}
+
+{
+  function openFile(info) {
+    assert.strictEqual(info.loopCount, 1);
+    // 1. ? event
+    assert.strictEqual(info.events, 1);
+
+    fs.open(__filename, 'r', (err) => {
+      assert.ifError(err);
+      safeMetricsInfo(afterOpenFile);
+    });
+  }
+
+  function afterOpenFile(info) {
+    assert.strictEqual(info.loopCount, 2);
+    // 1. ? event
+    // 2. uv_fs_open
+    assert.strictEqual(info.events, 2);
+
+    fs.readFile(__filename, (err) => {
+      assert.ifError(err);
+      safeMetricsInfo(afterReadFile);
+    });
+  }
+
+  function afterReadFile(info) {
+    assert.strictEqual(info.loopCount, 6);
+    // 1. ? event
+    assert.strictEqual(info.events, 6);
+    // 1. ?
+  }
+
+  safeMetricsInfo(openFile);
+}
\ No newline at end of file
diff --git a/test/parallel/test-performance-nodetiming-uvmetricsinfo.js b/test/parallel/test-performance-nodetiming-uvmetricsinfo.js
index bdab0925dbce4c..3d32e0deb72e94 100644
--- a/test/parallel/test-performance-nodetiming-uvmetricsinfo.js
+++ b/test/parallel/test-performance-nodetiming-uvmetricsinfo.js
@@ -1,74 +1,20 @@
 'use strict';
 
-require('../common');
-
-const fixtures = require('../common/fixtures');
-
-const filepath = fixtures.path('x.txt');
+const common = require('../common');
+common.skipIfWorker();
 
+const { spawnSync } = require('node:child_process');
 const assert = require('node:assert');
-const fs = require('node:fs');
-const { performance } = require('node:perf_hooks');
-
-const { nodeTiming } = performance;
-
-function safeMetricsInfo(cb) {
-  setImmediate(() => {
-    const info = nodeTiming.uvMetricsInfo;
-    cb(info);
-  });
-}
-
-{
-  const info = nodeTiming.uvMetricsInfo;
-  assert.strictEqual(info.loopCount, 0);
-  assert.strictEqual(info.events, 0);
-  // This is the only part of the test that we test events waiting
-  // Adding checks for this property will make the test flaky
-  // as it can be highly influenced by race conditions.
-  assert.strictEqual(info.eventsWaiting, 0);
-}
+const fixtures = require('../common/fixtures');
 
-{
-  // The synchronous call should obviously not affect the uv metrics
-  const fd = fs.openSync(filepath, 'r');
-  fs.readFileSync(fd);
-  const info = nodeTiming.uvMetricsInfo;
-  assert.strictEqual(info.loopCount, 0);
-  assert.strictEqual(info.events, 0);
-  assert.strictEqual(info.eventsWaiting, 0);
-}
+const file = fixtures.path('test-nodetiming-uvmetricsinfo.js');
 
 {
-  function openFile(info) {
-    assert.strictEqual(info.loopCount, 1);
-    // 1. ? event
-    assert.strictEqual(info.events, 1);
-
-    fs.open(filepath, 'r', (err) => {
-      assert.ifError(err);
-      safeMetricsInfo(afterOpenFile);
-    });
-  }
-
-  function afterOpenFile(info) {
-    assert.strictEqual(info.loopCount, 2);
-    // 1. ? event
-    // 2. uv_fs_open
-    assert.strictEqual(info.events, 2);
-
-    fs.readFile(filepath, (err) => {
-      assert.ifError(err);
-      safeMetricsInfo(afterReadFile);
-    });
-  }
-
-  function afterReadFile(info) {
-    assert.strictEqual(info.loopCount, 6);
-    // 1. ? event
-    assert.strictEqual(info.events, 6);
-    // 1. ?
-  }
-
-  safeMetricsInfo(openFile);
+  const { status, stderr } = spawnSync(
+    process.execPath,
+    [
+      file,
+    ],
+  );
+  assert.strictEqual(status, 0, stderr.toString());
 }

From 391ce64ee4355f07f5efaea07eb9ccb5ce40d99f Mon Sep 17 00:00:00 2001
From: RafaelGSS <rafael.nunu@hotmail.com>
Date: Thu, 29 Aug 2024 10:33:49 -0300
Subject: [PATCH 8/9] fixup! add a comment for the test guarantees

---
 .../fixtures/test-nodetiming-uvmetricsinfo.js | 24 +++----------------
 1 file changed, 3 insertions(+), 21 deletions(-)

diff --git a/test/fixtures/test-nodetiming-uvmetricsinfo.js b/test/fixtures/test-nodetiming-uvmetricsinfo.js
index 484070103f6e05..3b66aefba23063 100644
--- a/test/fixtures/test-nodetiming-uvmetricsinfo.js
+++ b/test/fixtures/test-nodetiming-uvmetricsinfo.js
@@ -1,3 +1,6 @@
+// Enforcing strict checks on the order or number of events across different
+// platforms can be tricky and unreliable due to various factors.
+// As a result, this test relies on the `uv_metrics_info` call instead.
 const { performance } = require('node:perf_hooks');
 const assert = require('node:assert');
 const fs = require('node:fs');
@@ -33,8 +36,6 @@ function safeMetricsInfo(cb) {
 {
   function openFile(info) {
     assert.strictEqual(info.loopCount, 1);
-    // 1. ? event
-    assert.strictEqual(info.events, 1);
 
     fs.open(__filename, 'r', (err) => {
       assert.ifError(err);
@@ -42,24 +43,5 @@ function safeMetricsInfo(cb) {
     });
   }
 
-  function afterOpenFile(info) {
-    assert.strictEqual(info.loopCount, 2);
-    // 1. ? event
-    // 2. uv_fs_open
-    assert.strictEqual(info.events, 2);
-
-    fs.readFile(__filename, (err) => {
-      assert.ifError(err);
-      safeMetricsInfo(afterReadFile);
-    });
-  }
-
-  function afterReadFile(info) {
-    assert.strictEqual(info.loopCount, 6);
-    // 1. ? event
-    assert.strictEqual(info.events, 6);
-    // 1. ?
-  }
-
   safeMetricsInfo(openFile);
 }
\ No newline at end of file

From 0e9cf0ea6bba87a11d74a98144b6d622766d5052 Mon Sep 17 00:00:00 2001
From: RafaelGSS <rafael.nunu@hotmail.com>
Date: Thu, 29 Aug 2024 12:36:03 -0300
Subject: [PATCH 9/9] fixup! fixup! add a comment for the test guarantees

---
 test/fixtures/test-nodetiming-uvmetricsinfo.js | 1 -
 1 file changed, 1 deletion(-)

diff --git a/test/fixtures/test-nodetiming-uvmetricsinfo.js b/test/fixtures/test-nodetiming-uvmetricsinfo.js
index 3b66aefba23063..59b1cc8ebf11f0 100644
--- a/test/fixtures/test-nodetiming-uvmetricsinfo.js
+++ b/test/fixtures/test-nodetiming-uvmetricsinfo.js
@@ -39,7 +39,6 @@ function safeMetricsInfo(cb) {
 
     fs.open(__filename, 'r', (err) => {
       assert.ifError(err);
-      safeMetricsInfo(afterOpenFile);
     });
   }