Benchmark: Overhead of saving and restoring context state 3

HTML Preparation code:

<canvas id="canvas" width="800" height="300"></canvas>

Script Preparation code:

$canvas = document.getElementById('canvas');
$context = $canvas.getContext('2d');
$context.clearRect(0, 0, 800, 300);

$iterations = 500;

Tests:

Not saving and restoring context state
for (let i=0; i<$iterations; ++i) { $context.fillStyle = 'rgba(100,150,200,0.9)'; $context.fillRect(0, 0, 1, 1); }
Saving and restoring context state
for (let i=0; i<$iterations; ++i) { const {fillStyle} = $context; $context.fillStyle = 'rgba(100,150,200,0.9)'; $context.fillRect(0, 0, 1, 1); $context.fillStyle = fillStyle; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Not saving and restoring context state
Saving and restoring context state

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/116.0.5845.2294 YaBrowser/23.9.0.2294 Yowser/2.5 Safari/537.36

Browser/OS: Yandex Browser 23 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Not saving and restoring context state	1447.6 Ops/sec
Saving and restoring context state	792.4 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into explaining the provided benchmark.

**Benchmark Overview**

The benchmark measures the overhead of saving and restoring context state in JavaScript. It tests two approaches: one where the context state is not saved, and another where it is saved.

**Script Preparation Code**

The script preparation code sets up a canvas element and its 2D drawing context:
```javascript
$canvas = document.getElementById('canvas');
$context = $canvas.getContext('2d');
$context.clearRect(0, 0, 800, 300);
```
This clears the canvas to ensure a consistent starting point for each benchmark run.

**Html Preparation Code**

The HTML preparation code defines an empty canvas element with a width and height:
```html
<canvas id="canvas" width="800" height="300"></canvas>
```
This ensures that all browsers will see the same initial state for the canvas.

**Individual Test Cases**

There are two test cases:

1. **Not saving and restoring context state**
```javascript
for (let i=0; i<$iterations; ++i) {
  $context.fillStyle = 'rgba(100,150,200,0.9)';
  $context.fillRect(0, 0, 1, 1);
}
```
This test case simply draws a single pixel on the canvas repeatedly using the `fillStyle` property directly.

2. **Saving and restoring context state**
```javascript
for (let i=0; i<$iterations; ++i) {
  const {fillStyle} = $context;
  $context.fillStyle = 'rgba(100,150,200,0.9)';
  $context.fillRect(0, 0, 1, 1);
  $context.fillStyle = fillStyle;
}
```
This test case saves the `fillStyle` property before drawing a pixel, restores it immediately after drawing, and then draws another pixel. This simulates saving and restoring context state.

**Pros and Cons**

* **Not Saving and Restoring Context State**
	+ Pros: Simple and straightforward, minimal overhead.
	+ Cons: May lead to inconsistent results due to caching or other optimizations.
* **Saving and Restoring Context State**
	+ Pros: More accurate representation of real-world use cases, can help identify performance issues related to context state management.
	+ Cons: Adds unnecessary overhead, may slow down benchmarked code.

**Library**

In this benchmark, `$context` is an alias for the 2D drawing context of a `<canvas>` element. The `fillStyle` property is used to set the color and alpha value for drawing pixels on the canvas.

**Special JS Feature or Syntax**

None are explicitly mentioned in the provided code. However, it's worth noting that the use of template literals (e.g., `$iterations = 500;`) is a feature introduced in ECMAScript 2015 (ES6).

**Alternatives**

Other ways to measure context state overhead might include:

* Using a library like `fast-canvas` or `jsdom` for more controlled canvas rendering.
* Adding additional rendering steps between the two test cases to increase the difference in execution time.
* Using different caching mechanisms or optimization techniques in the benchmarked code.

Keep in mind that these alternatives may change the nature of the benchmark and affect its results.

Related benchmarks:

Overhead of saving and restoring context state 3 (version: 0)

Comparing performance of: Not saving and restoring context state vs Saving and restoring context state

Created: 2 years ago by: Guest

Jump to the latest result

Not saving and restoring context state

Saving and restoring context state

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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