timers: run nextTicks after each immediate and timer

In order to better match the browser behaviour, run nextTicks (and
subsequently the microtask queue) after each individual Timer and
Immediate, rather than after the whole list is processed. The
current behaviour is somewhat of a performance micro-optimization
and also partly dictated by how timer handles were implemented.

PR-URL: https://github.com/nodejs/node/pull/22842
Fixes: https://github.com/nodejs/node/issues/22257
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>

1 files changed, 36 insertions, 0 deletions

diff --git a/benchmark/timers/timers-timeout-nexttick.js b/benchmark/timers/timers-timeout-nexttick.js
new file mode 100644
index 0000000000..781e505ae4
--- /dev/null
+++ b/benchmark/timers/timers-timeout-nexttick.js
@@ -0,0 +1,36 @@
+'use strict';
+const common = require('../common.js');
+
+// The following benchmark measures setting up n * 1e6 timeouts,
+// as well as scheduling a next tick from each timeout. Those
+// then get executed on the next uv tick.
+
+const bench = common.createBenchmark(main, {
+  n: [5e4, 5e6],
+});
+
+function main({ n }) {
+  let count = 0;
+
+  // Function tracking on the hidden class in V8 can cause misleading
+  // results in this benchmark if only a single function is used —
+  // alternate between two functions for a fairer benchmark.
+
+  function cb() {
+    process.nextTick(counter);
+  }
+  function cb2() {
+    process.nextTick(counter);
+  }
+  function counter() {
+    count++;
+    if (count === n)
+      bench.end(n);
+  }
+
+  for (var i = 0; i < n; i++) {
+    setTimeout(i % 2 ? cb : cb2, 1);
+  }
+
+  bench.start();
+}