timers: improve setImmediate() performance

This commit improves setImmediate() performance by moving the
try-finally block that wraps callback execution into a separate
function because currently v8 never tries to optimize functions
that contain try-finally blocks.

With this change, there is a ~20-40% improvement in the included
setImmediate() depth benchmarks. The breadth benchmarks show a slight
improvement.

PR-URL: https://github.com/nodejs/node/pull/4169
Reviewed-By: Minwoo Jung <jmwsoft@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>

4 files changed, 118 insertions, 0 deletions

diff --git a/benchmark/misc/set-immediate-breadth-args.js b/benchmark/misc/set-immediate-breadth-args.js
new file mode 100644
index 0000000000..6a904e2675
--- /dev/null
+++ b/benchmark/misc/set-immediate-breadth-args.js
@@ -0,0 +1,28 @@
+'use strict';
+
+const common = require('../common.js');
+const bench = common.createBenchmark(main, {
+  millions: [5]
+});
+
+function main(conf) {
+  const N = +conf.millions * 1e6;
+
+  process.on('exit', function() {
+    bench.end(N / 1e6);
+  });
+
+  function cb1(arg1) {}
+  function cb2(arg1, arg2) {}
+  function cb3(arg1, arg2, arg3) {}
+
+  bench.start();
+  for (let i = 0; i < N; i++) {
+    if (i % 3 === 0)
+      setImmediate(cb3, 512, true, null);
+    else if (i % 2 === 0)
+      setImmediate(cb2, false, 5.1);
+    else
+      setImmediate(cb1, 0);
+  }
+}
diff --git a/benchmark/misc/set-immediate-breadth.js b/benchmark/misc/set-immediate-breadth.js
new file mode 100644
index 0000000000..3d8b038342
--- /dev/null
+++ b/benchmark/misc/set-immediate-breadth.js
@@ -0,0 +1,21 @@
+'use strict';
+
+const common = require('../common.js');
+const bench = common.createBenchmark(main, {
+  millions: [10]
+});
+
+function main(conf) {
+  const N = +conf.millions * 1e6;
+
+  process.on('exit', function() {
+    bench.end(N / 1e6);
+  });
+
+  function cb() {}
+
+  bench.start();
+  for (let i = 0; i < N; i++) {
+    setImmediate(cb);
+  }
+}
diff --git a/benchmark/misc/set-immediate-depth-args.js b/benchmark/misc/set-immediate-depth-args.js
new file mode 100644
index 0000000000..1f12ae6ec7
--- /dev/null
+++ b/benchmark/misc/set-immediate-depth-args.js
@@ -0,0 +1,47 @@
+'use strict';
+
+const common = require('../common.js');
+const bench = common.createBenchmark(main, {
+  millions: [10]
+});
+
+function main(conf) {
+  const N = +conf.millions * 1e6;
+
+  process.on('exit', function() {
+    bench.end(N / 1e6);
+  });
+
+  function cb3(n, arg2, arg3) {
+    if (--n) {
+      if (n % 3 === 0)
+        setImmediate(cb3, n, true, null);
+      else if (n % 2 === 0)
+        setImmediate(cb2, n, 5.1);
+      else
+        setImmediate(cb1, n);
+    }
+  }
+  function cb2(n, arg2) {
+    if (--n) {
+      if (n % 3 === 0)
+        setImmediate(cb3, n, true, null);
+      else if (n % 2 === 0)
+        setImmediate(cb2, n, 5.1);
+      else
+        setImmediate(cb1, n);
+    }
+  }
+  function cb1(n) {
+    if (--n) {
+      if (n % 3 === 0)
+        setImmediate(cb3, n, true, null);
+      else if (n % 2 === 0)
+        setImmediate(cb2, n, 5.1);
+      else
+        setImmediate(cb1, n);
+    }
+  }
+  bench.start();
+  setImmediate(cb1, N);
+}
diff --git a/benchmark/misc/set-immediate-depth.js b/benchmark/misc/set-immediate-depth.js
new file mode 100644
index 0000000000..12b9cdc7e6
--- /dev/null
+++ b/benchmark/misc/set-immediate-depth.js
@@ -0,0 +1,22 @@
+'use strict';
+
+const common = require('../common.js');
+const bench = common.createBenchmark(main, {
+  millions: [10]
+});
+
+function main(conf) {
+  const N = +conf.millions * 1e6;
+  let n = N;
+
+  process.on('exit', function() {
+    bench.end(N / 1e6);
+  });
+
+  bench.start();
+  setImmediate(onNextTick);
+  function onNextTick() {
+    if (--n)
+      setImmediate(onNextTick);
+  }
+}