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process: improve nextTick performance #27347

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process: improve nextTick performance 
No longer check process.exiting on each tick add.
Cleaner emitDestroy with try/finally.
No longer use Reflect.apply since it's slower.
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@apapirovski
apapirovski committed Apr 22, 2019
commit 4d82fd811bd1df972f28da47280b23fc0aaca013
67 changes: 31 additions & 36 deletions lib/internal/process/task_queues.js
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Original file line number Diff line number Diff line change
@@ -1,6 +1,6 @@
'use strict';

const { FunctionPrototype, Reflect } = primordials;
const { FunctionPrototype } = primordials;

const {
// For easy access to the nextTick state in the C++ land,
Expand Down Expand Up @@ -62,25 +62,24 @@ function processTicksAndRejections() {
let tock;
do {
while (tock = queue.shift()) {
const asyncId = tock[async_id_symbol];
emitBefore(asyncId, tock[trigger_async_id_symbol]);
// emitDestroy() places the async_id_symbol into an asynchronous queue
// that calls the destroy callback in the future. It's called before
// calling tock.callback so destroy will be called even if the callback
// throws an exception that is handled by 'uncaughtException' or a
// domain.
// TODO(trevnorris): This is a bit of a hack. It relies on the fact
// that nextTick() doesn't allow the event loop to proceed, but if
// any async hooks are enabled during the callback's execution then
// this tock's after hook will be called, but not its destroy hook.
if (destroyHooksExist())
emitDestroy(asyncId);

const callback = tock.callback;
if (tock.args === undefined)
callback();
else
Reflect.apply(callback, undefined, tock.args);
const {
[async_id_symbol]: asyncId,
[trigger_async_id_symbol]: triggerAsyncId,
callback,
args
} = tock;

emitBefore(asyncId, triggerAsyncId);

try {
if (args === undefined)
callback();
else
callback(...args);
} finally {
if (destroyHooksExist())
emitDestroy(asyncId);
}

emitAfter(asyncId);
}
Expand All @@ -91,23 +90,18 @@ function processTicksAndRejections() {
}

class TickObject {
constructor(callback, args, triggerAsyncId) {
constructor(callback, args, asyncId, triggerAsyncId) {
// This must be set to null first to avoid function tracking
// on the hidden class, revisit in V8 versions after 6.2
// on the hidden class, revisit in V8 versions after 7.4
this.callback = null;
this.callback = callback;
this.args = args;

const asyncId = newAsyncId();
this[async_id_symbol] = asyncId;
this[trigger_async_id_symbol] = triggerAsyncId;

if (initHooksExist()) {
emitInit(asyncId,
'TickObject',
triggerAsyncId,
this);
}
if (initHooksExist())
emitInit(asyncId, 'TickObject', triggerAsyncId, this);
}
}

Expand All @@ -117,24 +111,25 @@ function nextTick(callback) {
if (typeof callback !== 'function')
throw new ERR_INVALID_CALLBACK(callback);

if (process._exiting)
return;

var args;
let args;
switch (arguments.length) {
case 1: break;
case 2: args = [arguments[1]]; break;
case 3: args = [arguments[1], arguments[2]]; break;
case 4: args = [arguments[1], arguments[2], arguments[3]]; break;
default:
args = new Array(arguments.length - 1);
for (var i = 1; i < arguments.length; i++)
for (let i = 1; i < arguments.length; i++)
args[i - 1] = arguments[i];
}

if (queue.isEmpty())
if (queue.isEmpty() && !process._exiting)
setHasTickScheduled(true);
queue.push(new TickObject(callback, args, getDefaultTriggerAsyncId()));

queue.push(new TickObject(callback,
args,
newAsyncId(),
getDefaultTriggerAsyncId()));
}

let AsyncResource;
Expand Down