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buffer: improve allocation performance

assertSize() is adjusted to be inlineable according to V8's default
function size limits when determining inlineability. This results in
up to 11% performance gains when allocating any kind of Buffer.

Avoid avoids use of in, resulting in ~50% improvement when creating
a Buffer from an array-like object.

PR-URL: #10443
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Сковорода Никита Андреевич <chalkerx@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
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1 parent 495213e commit 797495a84a7d3d4bbb849476022cc3058d8c2d99 @mscdex mscdex committed with evanlucas Dec 25, 2016
Showing with 14 additions and 5 deletions.
  1. +10 −1 benchmark/buffers/buffer-from.js
  2. +4 −4 lib/buffer.js
@@ -10,7 +10,8 @@ const bench = common.createBenchmark(main, {
'buffer',
'uint8array',
'string',
- 'string-base64'
+ 'string-base64',
+ 'object'
],
len: [10, 2048],
n: [1024]
@@ -25,6 +26,7 @@ function main(conf) {
const str = 'a'.repeat(len);
const buffer = Buffer.allocUnsafe(len);
const uint8array = new Uint8Array(len);
+ const obj = { length: null }; // Results in a new, empty Buffer
var i;
@@ -80,6 +82,13 @@ function main(conf) {
}
bench.end(n);
break;
+ case 'object':
+ bench.start();
+ for (i = 0; i < n * 1024; i++) {
+ Buffer.from(obj);
+ }
+ bench.end(n);
+ break;
default:
assert.fail(null, null, 'Should not get here');
}
View
@@ -108,6 +108,9 @@ Buffer.from = function(value, encodingOrOffset, length) {
Object.setPrototypeOf(Buffer, Uint8Array);
+// The 'assertSize' method will remove itself from the callstack when an error
+// occurs. This is done simply to keep the internal details of the
+// implementation from bleeding out to users.
function assertSize(size) {
let err = null;
@@ -117,9 +120,6 @@ function assertSize(size) {
err = new RangeError('"size" argument must not be negative');
if (err) {
- // The following hides the 'assertSize' method from the
- // callstack. This is done simply to hide the internal
- // details of the implementation from bleeding out to users.
Error.captureStackTrace(err, assertSize);
throw err;
}
@@ -258,7 +258,7 @@ function fromObject(obj) {
}
if (obj) {
- if ('length' in obj || isArrayBuffer(obj.buffer) ||
+ if (obj.length !== undefined || isArrayBuffer(obj.buffer) ||
isSharedArrayBuffer(obj.buffer)) {
if (typeof obj.length !== 'number' || obj.length !== obj.length) {
return new FastBuffer();

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