Benchmark: Overhead from creating closure

Script Preparation code:

var data = Array(200).map(_ => Math.floor(1000*Math.random()));


function foo() {
    let same = 0;
    for (let i = 0; i < data.length; i++) {
        for (let j = 0; j < data.length; j++) {
            if (i==j) continue;

            const compare = () => {
                if (data[i] == data[j]) {
                    same++;
                }
            }

            compare()
        }
    }

    return same
}

function bar() {
    let same = 0;

    const compare = (a, b) => {
        return a === b
    }

    for (let i = 0; i < data.length; i++) {
        for (let j = 0; j < data.length; j++) {
            if (i==j) continue;

            if (compare(data[i], data[j])) {
                same++;
            }
        }
    }

    return same
}

Tests:

create closure every time
foo()
reuse closure
bar()

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
create closure every time
reuse closure

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/110.0.0.0 Safari/537.36

Browser/OS: Chrome 110 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
create closure every time	151.0 Ops/sec
reuse closure	227.5 Ops/sec

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

LLMs can make mistakes. Check important info.

I'll break down the provided benchmark definition and test cases, explaining what's tested, the options compared, pros and cons of each approach, and other considerations.

**Benchmark Definition**

The provided JSON defines two benchmark definitions:

1. "Overhead from creating closure"
2. "Description": null
3. "Script Preparation Code":
```javascript
var data = Array(200).map(_ => Math.floor(1000*Math.random()));
```
This code creates an array of 200 random integers.

4. "Function foo()":
```javascript
function foo() {
    let same = 0;
    for (let i = 0; i < data.length; i++) {
        for (let j = 0; j < data.length; j++) {
            if (i==j) continue;

const compare = () => {
                if (data[i] == data[j]) {
                    same++;
                }
            };

compare();
        }
    }

return same;
}
```
This function creates a closure by defining an inner function `compare` inside the outer function `foo`. The `compare` function takes no arguments and checks if two elements in the `data` array are equal. If they are, it increments the `same` variable.

5. "Function bar()":
```javascript
function bar() {
    let same = 0;

const compare = (a, b) => {
        return a === b;
    };

for (let i = 0; i < data.length; i++) {
        for (let j = 0; j < data.length; j++) {
            if (i==j) continue;

if (compare(data[i], data[j])) {
                same++;
            }
        }
    }

return same;
}
```
This function also creates a closure, but with a different approach. It defines the `compare` function as an arrow function and passes two arguments to it.

**Options Compared**

The two benchmark definitions compare the overhead of creating closures in two different ways:

1. **Create closure every time**: The first benchmark definition uses the `foo()` function, which creates a new closure for each iteration of the outer loop.
2. **Reuse closure**: The second benchmark definition uses the `bar()` function, which creates a single closure and reuses it for all iterations of the outer loop.

**Pros and Cons**

1. **Create closure every time**:
	* Pros: Each iteration has its own separate closure, allowing for accurate measurement of overhead.
	* Cons: Creates multiple closures, potentially leading to slower performance due to increased memory allocation and garbage collection.
2. **Reuse closure**:
	* Pros: Only creates one closure, reducing memory allocation and garbage collection overhead.
	* Cons: The same closure is reused multiple times, which may lead to inaccurate measurements if the closure's behavior changes between iterations.

**Other Considerations**

* **Memory allocation**: Creating closures can lead to increased memory allocation, especially when dealing with large arrays. This can impact performance, especially in environments with limited memory.
* **Garbage collection**: JavaScript's garbage collector may interfere with benchmarking results, as it may collect the closure objects during execution.

**Individual Test Cases**

The test cases measure the overhead of creating closures in each function definition:

1. "create closure every time":
	* Measures the overhead of creating a new closure for each iteration.
2. "reuse closure":
	* Measures the overhead of reusing a single closure across multiple iterations.

**Library Usage**

Neither benchmark definition explicitly uses any libraries, but the `Array` class is used to create the array of random integers.

**Special JS Feature or Syntax**

None of the provided code snippets use any special JavaScript features or syntax beyond what's necessary for the benchmarking purpose.

Related benchmarks:

Overhead from creating closure (version: 0)

Comparing performance of: create closure every time vs reuse closure

Created: one year ago by: Guest

Jump to the latest result

create closure every time

reuse closure

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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