Benchmark: Shift loop vs unrolled

Tests:

Shift loop

const arr = [];
const ARRAY_SIZE = 5000;
for (let i = 0; i < ARRAY_SIZE; i++) {
  arr.push(i);
}
while(arr.length) {
  let index = arr.shift();
  index++;
}

AخA
 
const arr = [];const ARRAY_SIZE = 5000;for (let i = 0; i < ARRAY_SIZE; i++) {  arr.push(i);}while(arr.length) {  let index = arr.shift();  index++;}

Unrolled Loop

let arr = [];
const ARRAY_SIZE = 5000;
for (let i = 0; i < ARRAY_SIZE; i++) {
  arr.push(i);
}

for (let i = 0; i < arr.length; i++) {
  let index = arr[i];
  index++;
}
arr = [];

​x
 
let arr = [];const ARRAY_SIZE = 5000;for (let i = 0; i < ARRAY_SIZE; i++) {  arr.push(i);}​for (let i = 0; i < arr.length; i++) {  let index = arr[i];  index++;}arr = [];

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
Shift loop
Unrolled Loop

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 8 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/53.0.2785.113 Safari/537.36

Browser/OS: Chrome 53 on Mac OS X 10.10.5

View result in a separate tab

Test name	Executions per second
Shift loop	1887.8 Ops/sec
Unrolled Loop	19468.1 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 5 months ago):

Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net.

What is tested?

The provided JSON represents two benchmark test cases: "Shift loop" and "Unrolled Loop". Both tests aim to measure the performance difference between using the shift() method in a loop versus an unrolled approach (with an explicit index increment) to access the last element of an array.

Options compared:

Shift loop: This option uses the shift() method, which removes and returns the first element from the end of the array. The loop increments the index variable after each iteration.
Unrolled Loop: This option uses a for loop with an explicit index increment to access the last element of the array.

Pros and Cons:

Shift loop:
- Pros:
  - Simple and concise code.
  - Easy to understand and maintain.
- Cons:
  - May involve more overhead due to the shift() method, which can create a new array object each time it's called.
Unrolled Loop:
- Pros:
  - Can be faster since it avoids the overhead of creating a new array object.
- Cons:
  - Requires manual indexing and incrementing, which can lead to more complex code.

In general, the choice between these two approaches depends on the specific use case and performance requirements. If simplicity and ease of maintenance are prioritized, the shift loop might be a better choice. However, if raw performance is critical, the unrolled loop could provide a slight advantage.

Library:

None mentioned in the provided JSON. There are no external libraries required for these test cases.

Special JS feature or syntax:

There are no special JavaScript features or syntax used in these test cases. The code follows standard JavaScript conventions and does not utilize any advanced features like async/await, Promises, or modern language features.

Other alternatives:

For measuring performance differences between JavaScript implementations, other alternatives include:

jsbench: A benchmarking tool specifically designed for JavaScript.
Benchmark.js: A popular benchmarking library for JavaScript.
Performance.js: A benchmarking and profiling library for JavaScript applications.

These tools can provide more detailed insights into the performance characteristics of different JavaScript implementations and libraries.

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net.

**What is tested?**

The provided JSON represents two benchmark test cases: "Shift loop" and "Unrolled Loop". Both tests aim to measure the performance difference between using the `shift()` method in a loop versus an unrolled approach (with an explicit index increment) to access the last element of an array.

**Options compared:**

1. **Shift loop**: This option uses the `shift()` method, which removes and returns the first element from the end of the array. The loop increments the index variable after each iteration.
2. **Unrolled Loop**: This option uses a for loop with an explicit index increment to access the last element of the array.

**Pros and Cons:**

1. **Shift loop**:
	* Pros:
		+ Simple and concise code.
		+ Easy to understand and maintain.
	* Cons:
		+ May involve more overhead due to the `shift()` method, which can create a new array object each time it's called.
2. **Unrolled Loop**:
	* Pros:
		+ Can be faster since it avoids the overhead of creating a new array object.
	* Cons:
		+ Requires manual indexing and incrementing, which can lead to more complex code.

**Library:**

None mentioned in the provided JSON. There are no external libraries required for these test cases.

**Special JS feature or syntax:**

**Other alternatives:**

For measuring performance differences between JavaScript implementations, other alternatives include:

1. **jsbench**: A benchmarking tool specifically designed for JavaScript.
2. **Benchmark.js**: A popular benchmarking library for JavaScript.
3. **Performance.js**: A benchmarking and profiling library for JavaScript applications.

These tools can provide more detailed insights into the performance characteristics of different JavaScript implementations and libraries.

Related benchmarks:

Shift loop vs unrolled (version: 0)

Comparing performance of: Shift loop vs Unrolled Loop

Created: 8 years ago by: Guest

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