Benchmark: copy ArrayBuffer: Uint8Array.set vs by bytes

Script Preparation code:

var size = 0xFFFF;

var source = new Uint8Array(size);
var target = new Uint8Array(size);

for (let i = 0; i < size; i++) {
	source[i] = 100*Math.random();
}

Tests:

Uint8Array by byte
for (let i; i < size; i++) { target[i] = source[i]; }
Uint8Array with set
target.set(source);

Historical Performance Data aggregated from 17 community runs

Desktop Results:

Chrome 12 runs

Uint8Array by byte

18.0M/s

Uint8Array with set

817K/s

Fastest: Uint8Array by byte (22.0x faster)

View exact numbers

✓ Uint8Array by byte: 18,007,732 ops/sec
• Uint8Array with set: 817,024 ops/sec

Firefox 5 runs

Uint8Array by byte

1384.9M/s

Uint8Array with set

918K/s

Fastest: Uint8Array by byte (1509.2x faster)

View exact numbers

✓ Uint8Array by byte: 1,384,860,416 ops/sec
• Uint8Array with set: 917,607 ops/sec

Results show median performance across all community submissions. Run this benchmark yourself to verify on your device.

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Uint8Array by byte
Uint8Array with set

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/137.0.0.0 Safari/537.36 Edg/137.0.0.0

Browser/OS: Chrome 137 on Windows

View result in a separate tab

Uint8Array by byte

96.7M/s

Uint8Array with set

1.0M/s

View exact numbers

Test name	Executions per second
✓ Uint8Array by byte	96,664,152 Ops/sec
Uint8Array with set	1,018,248 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

LLMs can make mistakes. Check important info.

Let's break down the provided JSON benchmark and explain what's being tested, compared options, pros and cons, and other considerations.

**Benchmark Definition**

The benchmark is testing two different approaches to copy data from one `Uint8Array` to another:

1. `Uint8Array by byte`: This approach uses a traditional loop to iterate over each element of the source array and assign it to the corresponding index in the target array.
2. `Uint8Array with set`: This approach uses the `set()` method to copy the data from the source array to the target array.

**Options Compared**

The two options being compared are:

* **Manual loop**: The traditional loop-based approach using a for loop to iterate over each element of the source array.
* **Built-in `set()` method**: Using the `set()` method, which is a built-in method in JavaScript arrays, to copy data from one array to another.

**Pros and Cons**

* **Manual loop (Uint8Array by byte)**:
	+ Pros: This approach provides direct control over the copying process, allowing for optimizations such as caching or specialized implementations.
	+ Cons: This approach can be slower due to the overhead of explicit looping and indexing.
* **Built-in `set()` method (Uint8Array with set)**:
	+ Pros: This approach is generally faster since it leverages the optimized implementation of the `set()` method.
	+ Cons: This approach has less control over the copying process, which might limit optimization opportunities.

**Library/External Dependencies**

There are no external libraries or dependencies mentioned in the provided JSON benchmark.

**Special JS Feature/Syntax**

There are no special JavaScript features or syntax used in this benchmark. It's a straightforward comparison of two simple approaches.

**Other Alternatives**

Other alternatives to these two options might include:

* Using `Array.prototype.slice()` and assignment: This approach would create a new array with the desired range of elements from the source array and assign it to the target array.
* Using a specialized library like WebAssembly or SIMD instructions (if supported by JavaScript engines): These approaches could potentially provide even faster copying times, but might also add complexity and dependencies.

Overall, this benchmark provides a simple yet informative comparison of two common approaches for copying data from one `Uint8Array` to another in JavaScript.

copy ArrayBuffer: Uint8Array.set vs by bytes (version: 0)

Comparing performance of: `Uint8Array by byte vs Uint8Array with set`

Created: 2 years ago by: Guest

Go to the latest result

Uint8Array by byte

Uint8Array with set

Historical Performance Data aggregated from 17 community runs

Desktop Results:

Chrome 12 runs

Firefox 5 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

copy ArrayBuffer: Uint8Array.set vs by bytes (version: 0)

Comparing performance of: Uint8Array by byte vs Uint8Array with set

Created: 2 years ago by: Guest

Go to the latest result

Uint8Array by byte

Uint8Array with set

Historical Performance Data aggregated from 17 community runs

Desktop Results:

Chrome 12 runs

Firefox 5 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

Related benchmarks

Comparing performance of: `Uint8Array by byte vs Uint8Array with set`