feat(ext/node): perf_hooks.monitorEventLoopDelay() (#26905)

Fixes https://github.com/denoland/deno/issues/20961

Depends on https://github.com/denoland/deno_core/pull/965 and
https://github.com/denoland/deno_core/pull/966

Cargo.lock

@@ -1452,9 +1452,9 @@ dependencies = [
 
 [[package]]
 name = "deno_core"
-version = "0.319.0"
+version = "0.320.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e9dbb841f9850534320d8927dce53ca8d64bafbab5576c2a98f03f9e08534215"
+checksum = "f285eed7b072749f9c3a9c4cf2c9ebb06462a2c22afec94892a6684c38f32696"
 dependencies = [
  "anyhow",
  "bincode",
@@ -1929,6 +1929,7 @@ dependencies = [
  "stable_deref_trait",
  "thiserror",
  "tokio",
+ "tokio-eld",
  "url",
  "webpki-root-certs",
  "winapi",
@@ -1959,13 +1960,14 @@ dependencies = [
 
 [[package]]
 name = "deno_ops"
-version = "0.195.0"
+version = "0.196.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "797f348c38c07a5398bf790b280077c698e13fb49252f61ca6f6c5c616060292"
+checksum = "d35c75ae05062f37ec2ae5fd1d99b2dcdfa0aef70844d3706759b8775056c5f6"
 dependencies = [
  "proc-macro-rules",
  "proc-macro2",
  "quote",
+ "stringcase",
  "strum",
  "strum_macros",
  "syn 2.0.87",
@@ -3560,6 +3562,20 @@ dependencies = [
  "hashbrown 0.14.5",
 ]
 
+[[package]]
+name = "hdrhistogram"
+version = "7.5.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "765c9198f173dd59ce26ff9f95ef0aafd0a0fe01fb9d72841bc5066a4c06511d"
+dependencies = [
+ "base64 0.21.7",
+ "byteorder",
+ "crossbeam-channel",
+ "flate2",
+ "nom 7.1.3",
+ "num-traits",
+]
+
 [[package]]
 name = "heck"
 version = "0.4.1"
@@ -6406,9 +6422,9 @@ dependencies = [
 
 [[package]]
 name = "serde_v8"
-version = "0.228.0"
+version = "0.229.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bfe23e75c9a167f4e9d67a90d9fcaa622d1eec9aecad526c270e99a92f6915ff"
+checksum = "4e1dbbda82d67a393ea96f75d8383bc41fcd0bba43164aeaab599e1c2c2d46d7"
 dependencies = [
  "num-bigint",
  "serde",
@@ -6721,6 +6737,12 @@ dependencies = [
  "syn 2.0.87",
 ]
 
+[[package]]
+name = "stringcase"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "04028eeb851ed08af6aba5caa29f2d59a13ed168cee4d6bd753aeefcf1d636b0"
+
 [[package]]
 name = "strip-ansi-escapes"
 version = "0.2.0"
@@ -7522,6 +7544,16 @@ dependencies = [
  "windows-sys 0.48.0",
 ]
 
+[[package]]
+name = "tokio-eld"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9166030f05d6bc5642bdb8f8c2be31eb3c02cd465d662bcdc2df82d4aa41a584"
+dependencies = [
+ "hdrhistogram",
+ "tokio",
+]
+
 [[package]]
 name = "tokio-macros"
 version = "2.2.0"

Cargo.toml

@@ -46,7 +46,7 @@ repository = "https://github.com/denoland/deno"
 
 [workspace.dependencies]
 deno_ast = { version = "=0.43.3", features = ["transpiling"] }
-deno_core = { version = "0.319.0" }
+deno_core = { version = "0.320.0" }
 
 deno_bench_util = { version = "0.171.0", path = "./bench_util" }
 deno_config = { version = "=0.39.1", features = ["workspace", "sync"] }

ext/ffi/dlfcn.rs

@@ -15,6 +15,7 @@ use dlopen2::raw::Library;
 use serde::Deserialize;
 use serde_value::ValueDeserializer;
 use std::borrow::Cow;
+use std::cell::RefCell;
 use std::collections::HashMap;
 use std::ffi::c_void;
 use std::rc::Rc;
@@ -126,14 +127,17 @@ pub struct FfiLoadArgs {
 #[op2]
 pub fn op_ffi_load<'scope, FP>(
   scope: &mut v8::HandleScope<'scope>,
-  state: &mut OpState,
+  state: Rc<RefCell<OpState>>,
   #[serde] args: FfiLoadArgs,
 ) -> Result<v8::Local<'scope, v8::Value>, DlfcnError>
 where
   FP: FfiPermissions + 'static,
 {
-  let permissions = state.borrow_mut::<FP>();
+  let path = {
-  let path = permissions.check_partial_with_path(&args.path)?;
+    let mut state = state.borrow_mut();
+    let permissions = state.borrow_mut::<FP>();
+    permissions.check_partial_with_path(&args.path)?
+  };
 
   let lib = Library::open(&path).map_err(|e| {
     dlopen2::Error::OpeningLibraryError(std::io::Error::new(
@@ -215,6 +219,7 @@ where
     }
   }
 
+  let mut state = state.borrow_mut();
   let out = v8::Array::new(scope, 2);
   let rid = state.resource_table.add(resource);
   let rid_v8 = v8::Integer::new_from_unsigned(scope, rid);

ext/node/Cargo.toml

@@ -95,6 +95,7 @@ spki.workspace = true
 stable_deref_trait = "1.2.0"
 thiserror.workspace = true
 tokio.workspace = true
+tokio-eld = "0.2"
 url.workspace = true
 webpki-root-certs.workspace = true
 winapi.workspace = true

ext/node/lib.rs

@@ -427,6 +427,9 @@ deno_core::extension!(deno_node,
     ops::inspector::op_inspector_emit_protocol_event,
     ops::inspector::op_inspector_enabled,
   ],
+  objects = [
+    ops::perf_hooks::EldHistogram
+  ],
   esm_entry_point = "ext:deno_node/02_init.js",
   esm = [
     dir "polyfills",

ext/node/ops/mod.rs

@@ -10,6 +10,7 @@ pub mod idna;
 pub mod inspector;
 pub mod ipc;
 pub mod os;
+pub mod perf_hooks;
 pub mod process;
 pub mod require;
 pub mod tls;

ext/node/ops/perf_hooks.rs

@@ -0,0 +1,135 @@
+// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
+
+use deno_core::op2;
+use deno_core::GarbageCollected;
+
+use std::cell::Cell;
+
+#[derive(Debug, thiserror::Error)]
+pub enum PerfHooksError {
+  #[error(transparent)]
+  TokioEld(#[from] tokio_eld::Error),
+}
+
+pub struct EldHistogram {
+  eld: tokio_eld::EldHistogram<u64>,
+  started: Cell<bool>,
+}
+
+impl GarbageCollected for EldHistogram {}
+
+#[op2]
+impl EldHistogram {
+  // Creates an interval EldHistogram object that samples and reports the event
+  // loop delay over time.
+  //
+  // The delays will be reported in nanoseconds.
+  #[constructor]
+  #[cppgc]
+  pub fn new(#[smi] resolution: u32) -> Result<EldHistogram, PerfHooksError> {
+    Ok(EldHistogram {
+      eld: tokio_eld::EldHistogram::new(resolution as usize)?,
+      started: Cell::new(false),
+    })
+  }
+
+  // Disables the update interval timer.
+  //
+  // Returns true if the timer was stopped, false if it was already stopped.
+  #[fast]
+  fn enable(&self) -> bool {
+    if self.started.get() {
+      return false;
+    }
+
+    self.eld.start();
+    self.started.set(true);
+
+    true
+  }
+
+  // Enables the update interval timer.
+  //
+  // Returns true if the timer was started, false if it was already started.
+  #[fast]
+  fn disable(&self) -> bool {
+    if !self.started.get() {
+      return false;
+    }
+
+    self.eld.stop();
+    self.started.set(false);
+
+    true
+  }
+
+  // Returns the value at the given percentile.
+  //
+  // `percentile` ∈ (0, 100]
+  #[fast]
+  #[number]
+  fn percentile(&self, percentile: f64) -> u64 {
+    self.eld.value_at_percentile(percentile)
+  }
+
+  // Returns the value at the given percentile as a bigint.
+  #[fast]
+  #[bigint]
+  fn percentile_big_int(&self, percentile: f64) -> u64 {
+    self.eld.value_at_percentile(percentile)
+  }
+
+  // The number of samples recorded by the histogram.
+  #[getter]
+  #[number]
+  fn count(&self) -> u64 {
+    self.eld.len()
+  }
+
+  // The number of samples recorded by the histogram as a bigint.
+  #[getter]
+  #[bigint]
+  fn count_big_int(&self) -> u64 {
+    self.eld.len()
+  }
+
+  // The maximum recorded event loop delay.
+  #[getter]
+  #[number]
+  fn max(&self) -> u64 {
+    self.eld.max()
+  }
+
+  // The maximum recorded event loop delay as a bigint.
+  #[getter]
+  #[bigint]
+  fn max_big_int(&self) -> u64 {
+    self.eld.max()
+  }
+
+  // The mean of the recorded event loop delays.
+  #[getter]
+  fn mean(&self) -> f64 {
+    self.eld.mean()
+  }
+
+  // The minimum recorded event loop delay.
+  #[getter]
+  #[number]
+  fn min(&self) -> u64 {
+    self.eld.min()
+  }
+
+  // The minimum recorded event loop delay as a bigint.
+  #[getter]
+  #[bigint]
+  fn min_big_int(&self) -> u64 {
+    self.eld.min()
+  }
+
+  // The standard deviation of the recorded event loop delays.
+  #[getter]
+  fn stddev(&self) -> f64 {
+    self.eld.stdev()
+  }
+}

ext/node/polyfills/perf_hooks.ts

@@ -8,6 +8,7 @@ import {
   performance as shimPerformance,
   PerformanceEntry,
 } from "ext:deno_web/15_performance.js";
+import { EldHistogram } from "ext:core/ops";
 
 class PerformanceObserver {
   static supportedEntryTypes: string[] = [];
@@ -89,10 +90,11 @@ const performance:
     ) => shimPerformance.dispatchEvent(...args),
   };
 
-const monitorEventLoopDelay = () =>
+function monitorEventLoopDelay(options = {}) {
-  notImplemented(
+  const { resolution = 10 } = options;
-    "monitorEventLoopDelay from performance",
+
-  );
+  return new EldHistogram(resolution);
+}
 
 export default {
   performance,

tests/unit_node/perf_hooks_test.ts

@@ -5,7 +5,7 @@ import {
   performance,
   PerformanceObserver,
 } from "node:perf_hooks";
-import { assertEquals, assertThrows } from "@std/assert";
+import { assert, assertEquals, assertThrows } from "@std/assert";
 
 Deno.test({
   name: "[perf_hooks] performance",
@@ -73,11 +73,16 @@ Deno.test("[perf_hooks]: eventLoopUtilization", () => {
   assertEquals(typeof obj.utilization, "number");
 });
 
-Deno.test("[perf_hooks]: monitorEventLoopDelay", () => {
+Deno.test("[perf_hooks]: monitorEventLoopDelay", async () => {
-  const e = assertThrows(() => {
+  const e = monitorEventLoopDelay();
-    monitorEventLoopDelay({ resolution: 1 });
+  assertEquals(e.count, 0);
-  });
+  e.enable();
 
-  // deno-lint-ignore no-explicit-any
+  await new Promise((resolve) => setTimeout(resolve, 100));
-  assertEquals((e as any).code, "ERR_NOT_IMPLEMENTED");
+
+  assert(e.min > 0);
+  assert(e.minBigInt > 0n);
+  assert(e.count > 0);
+
+  e.disable();
 });