Benchmark: Shifted Integer vs Array vs Uint8Array

Script Preparation code:

var int = 0
var arr = []
arr.length = 8
arr.fill(0)
var u8 = new Uint8Array(1)

Tests:

Shifted Integer
for (let i = 0; i < 1000; i +=1) { int = ((int << 1) | 1) & ~(i & 1) & 255 } console.info(int)
Array
for (let i = 0; i < 1000; i +=1) { arr.push(i & 1) arr.shift() } console.info(arr)
Uint8Array
for (let i = 0; i < 1000; i +=1) { u8 = ((u8 << 1) | 1) & ~(i & 1) } console.info(u8)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Shifted Integer
Array
Uint8Array

Fastest: N/A

Slowest: N/A

Latest run results:

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

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Let's break down the provided benchmark and its test cases.

**Benchmark Overview**

The provided JSON represents a JavaScript microbenchmarking framework, MeasureThat.net. The goal of this benchmark is to compare the performance of three different approaches for implementing bitwise shift operations on integers:

1. Shifted Integer
2. Array
3. Uint8Array

**Test Case 1: Shifted Integer**

This test case uses a simple loop that performs a series of bitwise shift and AND operations on an integer variable `int`. The operation is as follows:
```javascript
int = ((int << 1) | 1) & ~(i & 1) & 255
```
The pros of this approach are:

* It only requires a single loop iteration for each iteration of the outer loop.
* It uses bitwise shift and AND operations, which are likely to be optimized by modern CPU architectures.

However, the cons are:

* It relies on the `~` operator, which may not be as efficient as other methods in some cases (e.g., when `i & 1` is always zero).
* It uses a fixed value of 255, which might not be optimal for all possible inputs.

**Test Case 2: Array**

This test case pushes values onto an array and then shifts the last element off the array using the `shift()` method. The operation is as follows:
```javascript
arr.push(i & 1)
arr.shift()
```
The pros of this approach are:

* It uses a standard JavaScript array method, which is likely to be optimized by modern browsers.
* It avoids the use of bitwise shift and AND operations, making it potentially more readable.

However, the cons are:

* It creates a new element on each iteration, which can lead to memory allocations and deallocations that might affect performance.
* The `shift()` method may not be as efficient as other methods for shifting elements in an array (e.g., when using native code).

**Test Case 3: Uint8Array**

This test case uses the `Uint8Array` class to create a buffer with a single element. It then performs a bitwise shift operation on this buffer using the following code:
```javascript
u8 = ((u8 << 1) | 1)
```
The pros of this approach are:

* It avoids creating an array or modifying it in place, which can lead to memory allocations and deallocations.
* It uses a `Uint8Array`, which is a typed array that may be optimized for specific use cases (e.g., when working with binary data).

However, the cons are:

* It relies on the `<<` operator, which might not be as efficient as other methods in some cases (e.g., when working with large values).
* The code assumes that the `u8` buffer has a single element, which may lead to errors if it's modified or extended.

**Library Usage**

None of the test cases use external libraries. However, they do rely on built-in JavaScript features and native browser functions (e.g., `push()` and `shift()` methods).

**Special JS Features/Syntax**

None of the test cases explicitly use special JavaScript features like `let` or `const`, nor do they use ES6+ syntax. The code is written in a style that's compatible with older browsers.

**Other Alternatives**

There are several alternative approaches to benchmarking this operation, including:

* Using native code (e.g., Assembly) to implement the bitwise shift operations.
* Using specialized libraries or frameworks that provide optimized implementations of bitwise shift operations (e.g., `Bitwise` library).
* Writing custom performance-critical code using languages like C++ or Rust.

Keep in mind that these alternatives may not be as widely supported or compatible with modern browsers, and might require more expertise to set up and maintain.

Related benchmarks:

Shifted Integer vs Array vs Uint8Array (version: 0)

Comparing performance of: Shifted Integer vs Array vs Uint8Array

Created: 7 years ago by: Guest

Jump to the latest result

Shifted Integer

Array

Uint8Array

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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