buffer: make FastBuffer safe to construct

[aduh95]

Default constructor iterates over the argument when calling the super constructor, we can get better result by passing an exact number of arguments on Apple Silicon processors.

Benchmark I run locally

 confidence improvement accuracy (*) (**) (***)
buffers/buffer-creation.js n=600000 len=10 type='fast-alloc-fill' *** 3.12 % ±1.34% ±1.79% ±2.34%
buffers/buffer-creation.js n=600000 len=10 type='fast-alloc' 1.34 % ±1.37% ±1.83% ±2.41%
buffers/buffer-creation.js n=600000 len=10 type='fast-allocUnsafe' *** 2.81 % ±0.22% ±0.29% ±0.38%
buffers/buffer-creation.js n=600000 len=10 type='slow-allocUnsafe' *** 1.06 % ±0.47% ±0.63% ±0.82%
buffers/buffer-creation.js n=600000 len=1024 type='fast-alloc-fill' *** 2.07 % ±0.66% ±0.88% ±1.15%
buffers/buffer-creation.js n=600000 len=1024 type='fast-alloc' 1.10 % ±1.42% ±1.89% ±2.47%
buffers/buffer-creation.js n=600000 len=1024 type='fast-allocUnsafe' *** 2.04 % ±0.78% ±1.04% ±1.35%
buffers/buffer-creation.js n=600000 len=1024 type='slow-allocUnsafe' 1.22 % ±3.00% ±4.00% ±5.21%
buffers/buffer-creation.js n=600000 len=4096 type='fast-alloc-fill' -0.57 % ±0.69% ±0.92% ±1.19%
buffers/buffer-creation.js n=600000 len=4096 type='fast-alloc' -0.55 % ±0.65% ±0.86% ±1.12%
buffers/buffer-creation.js n=600000 len=4096 type='fast-allocUnsafe' *** 6.19 % ±1.30% ±1.72% ±2.24%
buffers/buffer-creation.js n=600000 len=4096 type='slow-allocUnsafe' *** 5.92 % ±1.09% ±1.46% ±1.90%
buffers/buffer-creation.js n=600000 len=8192 type='fast-alloc-fill' 0.88 % ±0.98% ±1.30% ±1.70%
buffers/buffer-creation.js n=600000 len=8192 type='fast-alloc' -0.22 % ±1.16% ±1.54% ±2.00%
buffers/buffer-creation.js n=600000 len=8192 type='fast-allocUnsafe' 0.81 % ±1.50% ±2.00% ±2.62%
buffers/buffer-creation.js n=600000 len=8192 type='slow-allocUnsafe' 1.11 % ±1.17% ±1.56% ±2.03%
Be aware that when doing many comparisons the risk of a false-positive
result increases. In this case there are 16 comparisons, you can thus
expect the following amount of false-positive results:
0.80 false positives, when considering a 5% risk acceptance (*, **, ***),
0.16 false positives, when considering a 1% risk acceptance (**, ***),
0.02 false positives, when considering a 0.1% risk acceptance (***)

Related Issues

Refs: #36428
Refs: #36532

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• commit message follows commit guidelines

[aduh95]

Benchmark CI: https://ci.nodejs.org/view/Node.js%20benchmark/job/benchmark-node-micro-benchmarks/774/
Benchmark CI: https://ci.nodejs.org/view/Node.js%20benchmark/job/benchmark-node-micro-benchmarks/775/

[aduh95]

Benchmark results are not as good as the one I got locally, that might be related to using a different OS / architecture, not sure 🤔

@mscdex FYI

Details

 confidence improvement accuracy (*) (**) (***)
buffers/buffer-creation.js n=600000 len=1024 type='fast-alloc' -0.65 % ±5.67% ±7.55% ±9.84%
buffers/buffer-creation.js n=600000 len=1024 type='fast-alloc-fill' 3.19 % ±6.33% ±8.42% ±10.96%
buffers/buffer-creation.js n=600000 len=1024 type='fast-allocUnsafe' 1.59 % ±4.97% ±6.61% ±8.61%
buffers/buffer-creation.js n=600000 len=1024 type='slow-allocUnsafe' -3.15 % ±4.80% ±6.39% ±8.32%
buffers/buffer-creation.js n=600000 len=10 type='fast-alloc' 4.20 % ±8.95% ±11.91% ±15.50%
buffers/buffer-creation.js n=600000 len=10 type='fast-alloc-fill' 0.17 % ±10.80% ±14.38% ±18.75%
buffers/buffer-creation.js n=600000 len=10 type='fast-allocUnsafe' -3.57 % ±7.19% ±9.58% ±12.49%
buffers/buffer-creation.js n=600000 len=10 type='slow-allocUnsafe' 0.30 % ±6.21% ±8.27% ±10.79%
buffers/buffer-creation.js n=600000 len=4096 type='fast-alloc' 2.64 % ±5.10% ±6.79% ±8.85%
buffers/buffer-creation.js n=600000 len=4096 type='fast-alloc-fill' -1.68 % ±4.13% ±5.49% ±7.15%
buffers/buffer-creation.js n=600000 len=4096 type='fast-allocUnsafe' * -5.78 % ±4.56% ±6.06% ±7.89%
buffers/buffer-creation.js n=600000 len=4096 type='slow-allocUnsafe' ** -5.83 % ±3.91% ±5.20% ±6.77%
buffers/buffer-creation.js n=600000 len=8192 type='fast-alloc' -1.86 % ±4.64% ±6.18% ±8.05%
buffers/buffer-creation.js n=600000 len=8192 type='fast-alloc-fill' * 4.20 % ±3.59% ±4.78% ±6.23%
buffers/buffer-creation.js n=600000 len=8192 type='fast-allocUnsafe' -4.04 % ±4.99% ±6.65% ±8.67%
buffers/buffer-creation.js n=600000 len=8192 type='slow-allocUnsafe' 2.05 % ±6.44% ±8.58% ±11.19%
Be aware that when doing many comparisons the risk of a false-positive
result increases. In this case there are 16 comparisons, you can thus
expect the following amount of false-positive results:
0.80 false positives, when considering a 5% risk acceptance (*, **, ***),
0.16 false positives, when considering a 1% risk acceptance (**, ***),
0.02 false positives, when considering a 0.1% risk acceptance (***)

 confidence improvement accuracy (*) (**) (***)
buffers/buffer-creation.js n=600000 len=1024 type='fast-alloc' -1.56 % ±4.32% ±5.75% ±7.49%
buffers/buffer-creation.js n=600000 len=1024 type='fast-alloc-fill' -3.01 % ±4.59% ±6.10% ±7.94%
buffers/buffer-creation.js n=600000 len=1024 type='fast-allocUnsafe' -0.74 % ±4.29% ±5.71% ±7.43%
buffers/buffer-creation.js n=600000 len=1024 type='slow-allocUnsafe' -0.80 % ±4.49% ±5.98% ±7.81%
buffers/buffer-creation.js n=600000 len=10 type='fast-alloc' 1.45 % ±7.79% ±10.37% ±13.50%
buffers/buffer-creation.js n=600000 len=10 type='fast-alloc-fill' 3.03 % ±6.52% ±8.68% ±11.31%
buffers/buffer-creation.js n=600000 len=10 type='fast-allocUnsafe' 4.72 % ±8.13% ±10.84% ±14.14%
buffers/buffer-creation.js n=600000 len=10 type='slow-allocUnsafe' 0.52 % ±8.99% ±11.96% ±15.56%
buffers/buffer-creation.js n=600000 len=4096 type='fast-alloc' 0.42 % ±3.72% ±4.95% ±6.44%
buffers/buffer-creation.js n=600000 len=4096 type='fast-alloc-fill' -4.15 % ±4.26% ±5.67% ±7.39%
buffers/buffer-creation.js n=600000 len=4096 type='fast-allocUnsafe' -3.64 % ±4.19% ±5.58% ±7.27%
buffers/buffer-creation.js n=600000 len=4096 type='slow-allocUnsafe' -1.67 % ±4.44% ±5.92% ±7.70%
buffers/buffer-creation.js n=600000 len=8192 type='fast-alloc' 2.27 % ±3.68% ±4.90% ±6.38%
buffers/buffer-creation.js n=600000 len=8192 type='fast-alloc-fill' 0.21 % ±4.48% ±5.96% ±7.76%
buffers/buffer-creation.js n=600000 len=8192 type='fast-allocUnsafe' -2.39 % ±3.93% ±5.24% ±6.84%
buffers/buffer-creation.js n=600000 len=8192 type='slow-allocUnsafe' 1.14 % ±4.32% ±5.74% ±7.48%
Be aware that when doing many comparisons the risk of a false-positive
result increases. In this case there are 16 comparisons, you can thus
expect the following amount of false-positive results:
0.80 false positives, when considering a 5% risk acceptance (*, **, ***),
0.16 false positives, when considering a 1% risk acceptance (**, ***),
0.02 false positives, when considering a 0.1% risk acceptance (***)

[aduh95]

From what I can see based on the architecture I have at my disposal, this PR is neutral for performance on x86 macOS & Linux, and improve the perf on arm64 macOS.

[mscdex]

I'm inclined to believe Jenkins on this one as this is literally the same behavior as before. If anything, I'd expect a minor perf hit because V8 may be able to optimize calling default constructors of built-in types.

[aduh95]

this is literally the same behavior as before

Except it doesn't use Array.prototype[Symbol.iterator]. Given the benchmark results, I should probably change the commit message to not give false hope on what this is actually doing.

[mscdex]

Except it doesn't use Array.prototype[Symbol.iterator]

I don't follow. What I'm referring to is the change in this PR:

From an implicit, inherited constructor:

classFastBufferextendsUint8Array{}

To an explicit constructor that passes the exact same parameters:

classFastBufferextendsUint8Array{// eslint-disable-next-line no-useless-constructorconstructor(bufferOrLength,byteOffset,length){super(bufferOrLength,byteOffset,length);}}

Neither of these should invoke anything Array-related.

[ExE-Boss]

@mscdex Except that a missing constructor in a derived class is equivalent to:

constructor(...args){super(...args)}

And the spread operator invokes the [Symbol.iterator] method, and if you were to do:

deleteArray.prototype[Symbol.iterator];new(classextendsObject{})();

You’ll get:

Uncaught TypeError: Found non-callable @@iterator

Until tc39/ecma262#2216 is implemented.

[mscdex]

I think if this is going to be merged, we should have at least a code comment describing why this is being done this way.

I'm +0 on this since it doesn't really seem to change much, at least with the Buffer creation benchmarks.

[aduh95]

Relevant spec section: https://tc39.es/ecma262/#sec-runtime-semantics-classdefinitionevaluation

If constructor is empty, then

If ClassHeritageopt is present, then

Let constructorText be the source text

constructor(...args) { super(...args); }

Note that there's also a difference because the super constructor always receive 3 arguments. According to the spec, this would cause a slight difference when new FastBuffer is invoqued with no arguments (there's a shortcut for that case); since the benchmark doesn't show any perf regression, that should be fine.

[aduh95]

Force pushed to fix the commit message.

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/35023/

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/35068/

[github-actions]

Landed in bd6f230...0187716