Benchmark: just another for loop performance 3

Script Preparation code:

var array = new Array(100000).fill(Math.random())

Tests:

cached
let tmp = []; let k = array.length; for (let i = 0; i < k; i++) { tmp.push(array[i]+i); }; console.log(tmp)
uncached
let tmp = []; for (let i = 0; i < array.length; i++) { tmp.push(array[i] + i); }; console.log(tmp);
forEach
let tmp = []; let i = 0; array.forEach(x => { tmp.push(x + i); i++; }); console.log(tmp);
for ... of
let tmp = []; let i = 0; for (let x of array) { tmp.push(x + i); i++; }; console.log(tmp);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
cached
uncached
forEach
for ... of

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

This benchmark does not have any results yet. Be the first one to run it!

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

LLMs can make mistakes. Check important info.

Let's dive into the provided benchmarking test cases.

**Benchmark Overview**

The provided benchmark measures the performance of three different loop approaches in JavaScript: cached loops, uncached loops, and two types of array iteration (forEach and for...of).

**Loop Approaches**

1. **Cached Loops**: These are loops where the loop counter is stored in a variable before the loop starts. This allows the compiler to optimize the loop by storing the counter value only once.
2. **Uncached Loops**: These are loops where the loop counter is not stored in a variable before the loop starts. In this case, the loop counter must be accessed every iteration.

**Comparison of Loop Approaches**

*   **Cached Loops vs Uncached Loops**: Cached loops tend to perform better than uncached loops because they reduce the number of memory accesses and register spills. This is due to the fact that the compiler can optimize cached loops by storing the loop counter value only once.
    *   **Pros**: Better performance, reduced memory accesses, and improved compilation optimization.
    *   **Cons**: Requires more code maintenance (adding variables), and potential issues with variable scoping.
*   **ForEach vs For...Of Loops**: Both of these loop types are optimized by the compiler for their specific use cases. However, they have different performance characteristics depending on the JavaScript engine and hardware architecture.

*   **ForEach Loop**:
        *   Pros: Good performance when working with existing array methods (e.g., `map`, `filter`), fewer register spills due to automatic increment of variable `i`.
        *   Cons: Poor performance when used directly, requires a separate loop for initialization and post-execution, which can lead to higher function call counts.
    *   **For...Of Loop**:
        *   Pros: Improved performance compared to traditional for loops (using the old way of declaration), better handling of some edge cases like zero array size.
        *   Cons: May have slower iteration times compared to traditional "for" loops.

**Libraries and Special Features**

The provided benchmark does not use any libraries or special JavaScript features. It relies solely on built-in JavaScript functionality for its test cases.

**Other Alternatives**

Some other loop optimization techniques that could be explored in a benchmark include:

*   **Native code optimization**: Some platforms provide native code compilation tools that allow developers to optimize performance-critical loops.
*   **Just-In-Time (JIT) compiler optimizations**: JIT compilers can optimize performance by analyzing execution patterns and generating optimized machine code.
*   **Multi-threading or parallel processing**: Modern CPU architectures often support multiple threads or cores, allowing for efficient parallel processing of certain types of loops.

Overall, the provided benchmark provides a good starting point for measuring the performance differences between various loop optimization techniques in JavaScript.

Related benchmarks:

just another for loop performance 3 (version: 0)

cached vs uncached

Comparing performance of: cached vs uncached vs forEach vs for ... of

Created: 4 years ago by: Guest

Jump to the latest result

cached

uncached

forEach

for ... of

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):