Benchmark: Loop Optimization Working

Loop Optimization Working (version: 1)

Checking differences between various for/while loops.

Comparing performance of: For loop, basic vs While loop, basic vs For loop, cached (inside for statement) vs For loop, cached (outside for statement) vs For loop, i-- (caching inside for loop) vs For loop, i-- (caching outside for loop) vs While loop, cached vs While loop, i-- vs map vs forEach

Created: 4 years ago by: Registered User

Jump to the latest result

Script Preparation code:

  var arr = [];
  for (var i = 0; i < 1000; i++) {
    arr[i] = i;
  }

  function someFn(ix) {
    return ix * 5 + 1 / 3 * 8;
  }

​x
 
  var arr = [];  for (var i = 0; i < 1000; i++) {    arr[i] = i;  }​  function someFn(ix) {    return ix * 5 + 1 / 3 * 8;  }

Tests:

For loop, basic
for (var i = 0; i < arr.length; i++) { someFn(arr[i]); }
for (var i = 0; i < arr.length; i++) {
someFn(arr[i]);
}
While loop, basic
var i = 0; while (i < arr.length) { someFn(arr[i]); i++; }
var i = 0;
while (i < arr.length) {
someFn(arr[i]);
i++;
}
For loop, cached (inside for statement)
for (var i = 0, len = arr.length; i < len; i++) { someFn(arr[i]); }
for (var i = 0, len = arr.length; i < len; i++) {
someFn(arr[i]);
}
For loop, cached (outside for statement)
var len = arr.length; for (var i = 0; i < len; i++) { someFn(arr[i]); }
var len = arr.length;
for (var i = 0; i < len; i++) {
someFn(arr[i]);
}
For loop, i-- (caching inside for loop)
for (var i = arr.length; i > 0; i--) { someFn(arr[i]); }
for (var i = arr.length; i > 0; i--) {
someFn(arr[i]);
}
For loop, i-- (caching outside for loop)
var i = arr.length; for (; i > 0; i--) { someFn(arr[i]); }
var i = arr.length;
for (; i > 0; i--) {
someFn(arr[i]);
}
While loop, cached
var len = arr.length; var i = 0; while(i < len){ someFn(arr[i]); i++; }
var len = arr.length;
var i = 0;
while(i < len){
someFn(arr[i]);
i++;
}
While loop, i--
var i = arr.length - 1; while(i > 0){ someFn(arr[i]); i--; }
var i = arr.length - 1;
while(i > 0){
someFn(arr[i]);
i--;
}
map
arr.map(i => someFn(i))
arr.map(i => someFn(i))
forEach
arr.forEach(i => someFn(i))
arr.forEach(i => someFn(i))

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Experimental features:

Memory measurements supported only in Chrome.
For precise memory measurements Chrome must be launched with --enable-precise-memory-info flag.
More information: Monitoring JavaScript Memory

Test case name	Result
For loop, basic
While loop, basic
For loop, cached (inside for statement)
For loop, cached (outside for statement)
For loop, i-- (caching inside for loop)
For loop, i-- (caching outside for loop)
While loop, cached
While loop, i--
map
forEach

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/84.0.4147.105 Safari/537.36

Browser/OS: Chrome 84 on Linux

View result in a separate tab

Test name	Executions per second
For loop, basic	2134.0 Ops/sec
While loop, basic	2198.2 Ops/sec
For loop, cached (inside for statement)	2927.5 Ops/sec
For loop, cached (outside for statement)	3325.2 Ops/sec
For loop, i-- (caching inside for loop)	3298.9 Ops/sec
For loop, i-- (caching outside for loop)	3220.6 Ops/sec
While loop, cached	2067.5 Ops/sec
While loop, i--	2114.1 Ops/sec
map	3484.8 Ops/sec
forEach	3860.6 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):

Let's dive into the world of JavaScript microbenchmarks!

What is tested on the provided JSON?

The provided JSON represents a set of test cases for measuring the performance of different loops and array operations in JavaScript.

Each test case consists of a Benchmark Definition string that describes the loop or array operation to be tested. The test cases cover various scenarios, including:

Basic for loops (with and without caching)
Basic while loops
For loops with caching inside and outside the loop
While loops with caching

Options compared

The benchmark compares the performance of each test case across different browsers and devices.

Pros and cons of different approaches:

Here's a brief overview of the pros and cons of each approach:

For loops with caching: This approach can lead to better performance when dealing with large arrays, as it avoids re-allocating memory for each iteration.
- Pros: Efficient use of memory, good performance
- Cons: May not be optimal for small arrays or other scenarios where caching is not necessary
For loops without caching: This approach can lead to better performance in some cases, such as when dealing with small arrays or when the loop body is computationally expensive.
- Pros: Can be faster than caching approach, good for small arrays
- Cons: May lead to slower performance with large arrays due to memory re-allocations
While loops: This approach can lead to better performance in some cases, such as when dealing with arrays of fixed size or when the loop body is computationally expensive.
- Pros: Can be faster than for loops, good for arrays of fixed size
- Cons: May not be optimal for general-purpose use cases

Other observations:

Browser variability: The benchmark results show significant variations between browsers, highlighting the importance of testing across different platforms and browsers.
Device variability: The benchmark also shows device-specific performance differences, emphasizing the need to test on various devices to ensure compatibility.

In summary, the provided JSON represents a comprehensive set of tests for measuring the performance of JavaScript loops and array operations. By analyzing the results, developers can gain insights into the trade-offs between different approaches and optimize their code for better performance across various scenarios.

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks!

**What is tested on the provided JSON?**

The provided JSON represents a set of test cases for measuring the performance of different loops and array operations in JavaScript.

Each test case consists of a `Benchmark Definition` string that describes the loop or array operation to be tested. The test cases cover various scenarios, including:

1. Basic for loops (with and without caching)
2. Basic while loops
3. For loops with caching inside and outside the loop
4. While loops with caching

**Options compared**

The benchmark compares the performance of each test case across different browsers and devices.

**Pros and cons of different approaches:**

Here's a brief overview of the pros and cons of each approach:

1. **For loops with caching**: This approach can lead to better performance when dealing with large arrays, as it avoids re-allocating memory for each iteration.
	* Pros: Efficient use of memory, good performance
	* Cons: May not be optimal for small arrays or other scenarios where caching is not necessary
2. **For loops without caching**: This approach can lead to better performance in some cases, such as when dealing with small arrays or when the loop body is computationally expensive.
	* Pros: Can be faster than caching approach, good for small arrays
	* Cons: May lead to slower performance with large arrays due to memory re-allocations
3. **While loops**: This approach can lead to better performance in some cases, such as when dealing with arrays of fixed size or when the loop body is computationally expensive.
	* Pros: Can be faster than for loops, good for arrays of fixed size
	* Cons: May not be optimal for general-purpose use cases

**Other observations:**

1. **Browser variability**: The benchmark results show significant variations between browsers, highlighting the importance of testing across different platforms and browsers.
2. **Device variability**: The benchmark also shows device-specific performance differences, emphasizing the need to test on various devices to ensure compatibility.

Related benchmarks: