Benchmark: slice vs subarray vs ArrayBuffer copy

Script Preparation code:

var data = [1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
var f32 = new Float32Array(data);

Tests:

subarray direct
var copy = f32.subarray(10, 16);
slice direct
var copy = f32.slice(10, 16);
ArrayBuffer copy
var copy = new Float32Array(f32.buffer, 10*4, 6);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
subarray direct
slice direct
ArrayBuffer copy

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/129.0.0.0 Safari/537.36 Edg/129.0.0.0

Browser/OS: Chrome 129 on Windows

View result in a separate tab

subarray direct

6.5M/s

slice direct

6.4M/s

ArrayBuffer copy

3.6M/s

View exact numbers

Test name	Executions per second
✓ subarray direct	6,522,495 Ops/sec
slice direct	6,380,646 Ops/sec
ArrayBuffer copy	3,564,905 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 benchmark and explain what's being tested, compared, and their pros and cons.

**Benchmark Test Case:**

The test case measures the performance of different approaches for copying a subset of data from an array:

1. `subarray` method
2. `slice` method
3. Creating a new `Float32Array` instance using the original array's buffer

**What is being tested?**

Each approach is compared to determine which one is fastest in terms of execution time.

**Options Compared:**

1. **subarray direct**: This involves creating a new subarray within the existing `Float32Array` instance, without allocating a new buffer or copying data.
2. **slice direct**: Similar to `subarray`, but using the `slice` method to create a new array view of the original data.
3. **ArrayBuffer copy**: Creating a new `Float32Array` instance by passing the original array's buffer and specifying the starting offset and length.

**Pros and Cons:**

1. **subarray direct**:
	* Pros: Fastest in terms of execution time, as it only requires creating a new subarray within the existing buffer.
	* Cons: Can be slower than `slice` if the original array is large and needs to be sliced multiple times, as this can lead to excessive copying within the browser's memory manager.
2. **slice direct**:
	* Pros: Slightly faster than `subarray` due to its optimized implementation, but still requires allocating a new buffer or copying data.
	* Cons: May incur additional overhead if the original array is large and needs to be sliced multiple times.
3. **ArrayBuffer copy**:
	* Pros: Can be faster in some cases, as it allows the browser to allocate a new buffer and copy data from the original array in a single operation.
	* Cons: Requires more memory allocation and copying than `subarray` or `slice`, making it slower for small arrays.

**Library/Feature Used:**

None specific, but the benchmark uses the built-in JavaScript APIs (`Float32Array`, `subarray`, `slice`, `ArrayBuffer`) without any external libraries.

**Special JS Feature/Syntax:**

The benchmark does not use any special JavaScript features or syntax beyond what's commonly available in modern browsers. However, it relies on a few advanced concepts:

* Buffers and arrays as typed data structures
* Views (subarrays and slices) for accessing parts of an array
* ArrayBuffer creation and management

**Other Alternatives:**

Some alternative approaches that could be tested instead of `subarray`, `slice`, or `ArrayBuffer copy` include:

* Using `TypedArray.prototype.set()` to set values in a new array, followed by copying the data from an existing array.
* Creating a custom function to manually iterate over the original array and allocate memory for the new array using `Uint8Array` or another typed array type.

These alternatives could provide interesting variations on the benchmark results, but would likely require more complex implementation and potentially different optimization strategies.

slice vs subarray vs ArrayBuffer copy (version: 0)

Comparing performance of: `subarray direct vs slice direct vs ArrayBuffer copy`

Created: 2 years ago by: Guest

Go to the latest result

subarray direct

slice direct

ArrayBuffer copy

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

slice vs subarray vs ArrayBuffer copy (version: 0)

Comparing performance of: subarray direct vs slice direct vs ArrayBuffer copy

Created: 2 years ago by: Guest

Go to the latest result

subarray direct

slice direct

ArrayBuffer copy

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: `subarray direct vs slice direct vs ArrayBuffer copy`