Benchmark: Uint32Array copy vs set

Script Preparation code:

var command = Math.floor(Math.random() * 65536),
    operation = Math.floor(Math.random() * 65536),
    cellId = Math.floor(Math.random() * 60),
    buffer = new Uint8Array(Array.from({
        length: Math.floor(Math.random() * 100)
    }).map(() => Math.floor(Math.random() * 256))).buffer,
    reverse = [0, 3],
    HEADER_SIZE = 8,
    MSG_HEADER_LEN = 32;

Tests:

set
const dataLength = buffer.byteLength; const content = new ArrayBuffer(MSG_HEADER_LEN + dataLength); const contentView = new Uint32Array(content, 0, HEADER_SIZE); if (dataLength) { const srcBuffer = new Uint8Array(buffer); const dstBuffer = new Uint8Array(content); dstBuffer.set(srcBuffer, MSG_HEADER_LEN); }
copy
const dataLength = buffer.byteLength; const content = new ArrayBuffer(MSG_HEADER_LEN + dataLength); const contentView = new Uint32Array(content, 0, HEADER_SIZE); if (dataLength) { const srcBuffer = new Uint8Array(buffer); const dstBuffer = new Uint8Array(content, MSG_HEADER_LEN, dataLength); for (let index = 0; index < dataLength; index++) { dstBuffer[index] = srcBuffer[index]; } }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
set
copy

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net.

The provided benchmark is designed to compare two approaches for copying data between two Uint8Array buffers: `set` and `copy`. The test aims to determine which approach is faster.

**Benchmark Definition**

The benchmark definition provides a brief description of the test, but not its purpose. However, based on the script preparation code, we can infer that the test creates two buffers: `buffer` (a random-sized Uint8Array) and `content` (an ArrayBuffer with a fixed length of `MSG_HEADER_LEN + dataLength`, where `dataLength` is the byte length of `buffer`).

**Script Preparation Code**

The script preparation code defines several variables:

* `command`: a random number between 0 and 65535
* `operation`: another random number between 0 and 65535 (used for testing purposes)
* `cellId`: a random number between 0 and 59 (used for testing purposes)
* `buffer`: the Uint8Array buffer created earlier
* `reverse`: an array with two indices [0, 3]
* `HEADER_SIZE`: an integer constant representing the size of the header in bytes

The code also defines the content buffer as a new ArrayBuffer with a length of `MSG_HEADER_LEN + dataLength`, where `MSG_HEADER_LEN` is another constant.

**Html Preparation Code**

There is no HTML preparation code provided, which means that the test does not require any specific web page setup or execution environment.

**Test Cases**

The benchmark consists of two individual test cases:

1. **set**: This approach sets a portion of the content buffer using `dstBuffer.set(srcBuffer, MSG_HEADER_LEN)`. It assumes that the source and destination buffers have the same size.
2. **copy**: This approach copies data from the source buffer to the destination buffer using a loop: `for (let index = 0; index < dataLength; index++) { dstBuffer[index] = srcBuffer[index]; }`

**Options Compared**

The benchmark compares two options:

1. **set**: Uses `dstBuffer.set(srcBuffer, MSG_HEADER_LEN)` to set the portion of the content buffer.
2. **copy**: Uses a loop to manually copy the data from the source buffer to the destination buffer.

**Pros and Cons**

* **set**: Pros:
	+ Faster execution time (according to the benchmark results)
	+ Simpler code
Cons:
	+ Assumes that the source and destination buffers have the same size
* **copy**: Pros:
	+ More flexible, as it works with buffers of different sizes
Cons:
	+ Slower execution time (according to the benchmark results)

**Library**

The test uses the `Uint8Array` class from the JavaScript standard library, which is a typed array for representing unsigned 8-bit integers.

There are no external libraries or dependencies used in this benchmark.

**Special JS Feature or Syntax**

None of the options mentioned use any special JavaScript features or syntax. Both approaches rely on basic arithmetic operations and DOM methods (e.g., `set()`).

**Alternatives**

If you were to implement a similar benchmark, you might consider additional alternatives:

1. **ArrayBuffer**: You could test using an ArrayBuffer with a more complex data structure, such as an array of floats or integers.
2. ** DataView**: You could use the `DataView` class, which provides a way to access and manipulate binary data in typed arrays.
3. **WebAssembly**: You could create a benchmark that tests performance on WebAssembly (WASM) platforms, which can provide better performance for certain types of computations.

Keep in mind that MeasureThat.net is a specialized platform designed specifically for JavaScript microbenchmarks. If you were to implement a similar benchmark outside of this platform, you might need to adapt the code and test configuration to suit your specific use case or environment.

Latest run results:

Run details: (Test run date: 9 months ago)

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/121.0.0.0 Safari/537.36

Browser/OS: Chrome 121 on Linux

View result in a separate tab

Test name	Executions per second
set	949783.4 Ops/sec
copy	897629.8 Ops/sec

Related benchmarks:

Uint32Array copy vs set (version: 0)

Comparing performance of: set vs copy

Created: 9 months ago by: Guest

Jump to the latest result

set

copy

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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