Benchmark: Division by 1000 vs bitwise shifting approximation (1024)

Tests:

Division
(new Date).getTime() / 1000;
Bitwise
(new Date).getTime() >> 11;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Division
Bitwise

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36

Browser/OS: Chrome 131 on Windows

View result in a separate tab

Test name	Executions per second
Division	4656574.5 Ops/sec
Bitwise	4671261.0 Ops/sec

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

LLMs can make mistakes. Check important info.

I'd be happy to help you understand what's being tested in this JavaScript benchmark.

**Overview**

The provided JSON represents a microbenchmarking framework, specifically MeasureThat.net. The goal of this platform is to measure the performance differences between two approaches: using the `/` operator for division and an approximation method involving bitwise shifting.

**What's being tested?**

In essence, the test cases compare the execution time of two methods:

1. **Division**: Using the `/` operator to perform integer division.
2. **Bitwise**: Shifting the bits of the dividend by 11 positions to the right using the `>>` operator, which effectively divides by 1024.

**Options comparison**

The main options being compared are:

* **Division**: The traditional method using the `/` operator.
	+ Pros: Easy to understand and implement. Well-established.
	+ Cons: May incur unnecessary overhead due to the arithmetic operation.
* **Bitwise**: Approximating division using bitwise shifting.
	+ Pros: Potentially faster execution time due to reduced arithmetic overhead.
	+ Cons: Requires careful implementation to avoid overflow or underflow issues.

**Other considerations**

When implementing either approach, developers should be aware of potential pitfalls:

* Division by a large number like 1024 can lead to floating-point precision issues if not handled carefully.
* Bitwise shifting requires accurate calculation to avoid loss of precision.

**Library usage**

In the provided benchmark definition JSON, `new Date().getTime()` is used. This function returns the current time in milliseconds since the Unix epoch (January 1, 1970, 00:00:00 UTC). In this context, it's likely being used as a timing source to measure execution times.

**Special JS feature**

The test cases use the `>>` operator for bitwise shifting. This is a JavaScript-specific operator that shifts the bits of a number to the right by a specified number of positions. It's not part of the standard arithmetic operators but is supported in modern JavaScript engines.

**Other alternatives**

If you need alternative approaches, consider these options:

* **Use `Math.floor((new Date).getTime() / 1000) * 1024`**: This method uses integer division and multiplication to achieve a similar result.
* **Use a library like `big-integer` or `decimal.js` for accurate arithmetic operations**: These libraries can handle large numbers and provide precision control, but may introduce additional overhead.

Keep in mind that the choice of approach depends on your specific use case and performance requirements.

Related benchmarks:

Division by 1000 vs bitwise shifting approximation (1024) (version: 0)

Comparing performance of: Division vs Bitwise

Created: 8 years ago by: Guest

Jump to the latest result

Division

Bitwise

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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