Benchmark: Plus equals is slow

Tests:

Plus equals
let x = 0; for (var i=0; i < 1000; i++) { x += 2 + i; }
Plus
let x = 0; for (var i=0; i < 1000; i++) { x = x + 2 + 1 }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Plus equals
Plus

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/112.0.0.0 Safari/537.36

Browser/OS: Chrome 112 on Linux

View result in a separate tab

Test name	Executions per second
Plus equals	1871631.5 Ops/sec
Plus	1875641.8 Ops/sec

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

LLMs can make mistakes. Check important info.

I'll break down the benchmark and its test cases, explaining what's being tested, compared options, pros/cons, and other considerations.

**Benchmark Definition**

The provided `Json` file represents a benchmark definition for "Plus equals is slow". The description is cryptic ("Why the hell"), but it seems to be testing the performance of adding two numbers using the `+=` operator versus a more traditional addition assignment (`x = x + 2 + 1`) in a loop.

**Test Cases**

There are two test cases:

1. **"Plus equals"**: This benchmark definition is identical to the first line of the script:
```javascript
let x = 0;
for (var i=0; i < 1000; i++) {
  x += 2 + i;
}
```
This is essentially a simple loop that increments `x` using the `+=` operator.

2. **"Plus"**: This benchmark definition uses a more traditional addition assignment:
```javascript
let x = 0;
for (var i=0; i < 1000; i++) {
  x = x + 2 + 1;
}
```
This is similar to the previous test case, but with parentheses around the `+` operator.

**Comparison**

The two test cases are comparing the performance of using the `+=` operator versus a more traditional addition assignment. The pros and cons of these approaches:

* **`+=` operator**:
	+ Pros: concise, easy to read
	+ Cons: potentially slower due to the need to calculate a temporary value on the fly
* **Traditional addition assignment (`x = x + 2 + 1`)**:
	+ Pros: may be faster since it avoids calculating a temporary value
	+ Cons: less concise and harder to read

**Library**

In both test cases, there is no explicit library being used. However, the use of `var` for declaring the loop variable `i` suggests that this benchmark might be targeting older browsers or environments where strict mode has not been enabled.

**Special JS Feature/Syntax**

There are no special JavaScript features or syntax used in these test cases.

**Other Considerations**

When running benchmarks like this, it's essential to consider factors like:

* Cache locality: How does the loop iterate affect cache usage and performance?
* Branch prediction: Will the CPU correctly predict which branch to take (in this case, whether to use `+=` or traditional addition assignment)?
* Overhead of function calls: Are there any unnecessary function calls or allocations that could impact performance?

**Alternatives**

Other alternatives for testing similar benchmarks might include:

* Using a more modern loop variable declaration syntax (e.g., `let i = 0;`)
* Adding more complex operations to the loop (e.g., multiplication, division)
* Using different data structures or algorithms (e.g., arrays vs. linked lists)
* Including additional test cases for edge cases (e.g., negative numbers, NaNs)

Keep in mind that benchmarking can be a complex and nuanced field, and the specific options and considerations will depend on the target browser, hardware, and use case.

Related benchmarks:

Plus equals is slow (version: 0)

Why the hell

Comparing performance of: Plus equals vs Plus

Created: 8 years ago by: Guest

Jump to the latest result

Plus equals

Plus

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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