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lib: make queueMicrotask faster

No longer create an additional scope within queueMicrotask
in order to improve performance.

PR-URL: #27032
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: James M Snell <jasnell@gmail.com>
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apapirovski authored and danbev committed Mar 31, 2019
1 parent d3d4e10 commit 2c49e8b537a5fba07568c2363ba6a594caa74c17
@@ -0,0 +1,21 @@
'use strict';

const common = require('../common.js');
const bench = common.createBenchmark(main, {
n: [4e5]
});

function main({ n }) {
var j = 0;

function cb() {
j++;
if (j === n)
bench.end(n);
}

bench.start();
for (var i = 0; i < n; i++) {
queueMicrotask(cb);
}
}
@@ -0,0 +1,17 @@
'use strict';
const common = require('../common.js');
const bench = common.createBenchmark(main, {
n: [12e5]
});

function main({ n }) {
let counter = n;
bench.start();
queueMicrotask(onNextTick);
function onNextTick() {
if (--counter)
queueMicrotask(onNextTick);
else
bench.end(n);
}
}
@@ -37,6 +37,8 @@ const {
} = require('internal/errors').codes;
const FixedQueue = require('internal/fixed_queue');

const FunctionBind = Function.call.bind(Function.prototype.bind);

// *Must* match Environment::TickInfo::Fields in src/env.h.
const kHasTickScheduled = 0;

@@ -149,28 +151,32 @@ function createMicrotaskResource() {
});
}

function runMicrotask() {
this.runInAsyncScope(() => {
const callback = this.callback;
try {
callback();
} catch (error) {
// TODO(devsnek) remove this if
// https://bugs.chromium.org/p/v8/issues/detail?id=8326
// is resolved such that V8 triggers the fatal exception
// handler for microtasks
triggerFatalException(error);
} finally {
this.emitDestroy();
}
});
}

function queueMicrotask(callback) {
if (typeof callback !== 'function') {
throw new ERR_INVALID_ARG_TYPE('callback', 'function', callback);
}

const asyncResource = createMicrotaskResource();
asyncResource.callback = callback;

enqueueMicrotask(() => {
asyncResource.runInAsyncScope(() => {
try {
callback();
} catch (error) {
// TODO(devsnek) remove this if
// https://bugs.chromium.org/p/v8/issues/detail?id=8326
// is resolved such that V8 triggers the fatal exception
// handler for microtasks
triggerFatalException(error);
} finally {
asyncResource.emitDestroy();
}
});
});
enqueueMicrotask(FunctionBind(runMicrotask, asyncResource));
}

module.exports = {

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