Benchmark: Loop Optimization

Loop Optimization (version: 0)

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 forEach

Created: 7 years ago by: Guest

Jump to the latest result

Script Preparation code:

  var arr = [];
  for (var i = 0; i < 10000; i++) {
    arr.push(i);
  }

var sum = 0;

​x
 
  var arr = [];  for (var i = 0; i < 10000; i++) {    arr.push(i);  }​var sum = 0;

Tests:

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

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--
forEach

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 7 years ago)

User agent: Mozilla/5.0 (Linux; Android 6.0.1; SAMSUNG SM-T805 Build/MMB29K) AppleWebKit/537.36 (KHTML, like Gecko) SamsungBrowser/6.4 Chrome/56.0.2924.87 Safari/537.36

Browser/OS: Chrome 56 on Android 6.0.1

View result in a separate tab

Test name	Executions per second
For loop, basic	34.3 Ops/sec
While loop, basic	33.9 Ops/sec
For loop, cached (inside for statement)	45.5 Ops/sec
For loop, cached (outside for statement)	45.6 Ops/sec
For loop, i-- (caching inside for loop)	43.8 Ops/sec
For loop, i-- (caching outside for loop)	39.0 Ops/sec
While loop, cached	44.1 Ops/sec
While loop, i--	46.4 Ops/sec
forEach	51.7 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 7 months ago):

Let's dive into the world of JavaScript microbenchmarks.

The provided JSON represents a benchmarking test case for comparing the performance of different JavaScript loops. The main goal is to measure which loop type and caching approach yields the best execution speed.

Here are the options being compared:

For loop, basic: A traditional for loop that iterates over an array using arr.length as the condition.
While loop, basic: A while loop that continues to execute as long as a certain condition is true.
For loop, cached (inside): A for loop that uses a cached value of i to iterate over the array, reducing the number of times arr.length needs to be accessed.
For loop, cached (outside): Similar to the previous option, but the cached value is obtained before the loop starts.
While loop, cached: A while loop that caches the condition and updates it in each iteration.

The caching approaches aim to reduce the number of times arr.length or other expensive operations are performed, potentially improving performance.

Now, let's analyze the results:

The top-performing loops are those with caching: For loop, cached (outside) and While loop, cached.
The basic for and while loops, without caching, are significantly slower.
The caching approaches that use a cached value of i (either inside or outside the loop) outperform the ones that don't use caching.

In general, caching can be an effective way to improve performance in JavaScript by reducing the number of times expensive operations are performed. However, it's essential to note that the impact of caching will depend on the specific use case and implementation details.

To summarize:

Caching can improve performance in JavaScript loops.
The caching approach matters: using a cached value of i (either inside or outside) tends to be faster than not using caching at all.
Traditional for and while loops, without caching, are likely to be slower due to the repeated access to arr.length.

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks.

Here are the options being compared:

1. **For loop, basic**: A traditional for loop that iterates over an array using `arr.length` as the condition.
2. **While loop, basic**: A while loop that continues to execute as long as a certain condition is true.
3. **For loop, cached (inside)**: A for loop that uses a cached value of `i` to iterate over the array, reducing the number of times `arr.length` needs to be accessed.
4. **For loop, cached (outside)**: Similar to the previous option, but the cached value is obtained before the loop starts.
5. **While loop, cached**: A while loop that caches the condition and updates it in each iteration.

The caching approaches aim to reduce the number of times `arr.length` or other expensive operations are performed, potentially improving performance.

Now, let's analyze the results:

* The top-performing loops are those with caching: `For loop, cached (outside)` and `While loop, cached`.
* The basic for and while loops, without caching, are significantly slower.
* The caching approaches that use a cached value of `i` (either inside or outside the loop) outperform the ones that don't use caching.

To summarize:

* Caching can improve performance in JavaScript loops.
* The caching approach matters: using a cached value of `i` (either inside or outside) tends to be faster than not using caching at all.
* Traditional for and while loops, without caching, are likely to be slower due to the repeated access to `arr.length`.

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