Benchmark: Dataview vs Custom - Read uint8

Script Preparation code:

  var totalBytes = 1024 * 1024;
  var buffer = new ArrayBuffer(totalBytes);
  // fill
  var dv = new DataView(buffer);
  for (i=0; i<totalBytes; i++) {
  	 num = Math.floor(Math.random()*256);
  	 dv.setUint8(i,num,true);
  }
  
  function readUnsignedByte(stream){
         var l=stream[seek];
         seek=seek+1;return l;
  }
  	
  var seek=0;
  var stream = new Uint8Array(buffer);

Tests:

Dataview
for (i=0; i<totalBytes; i++) { num = dv.getUint8(i); }
Custom
for (i=0; i<totalBytes; i++) { num = readUnsignedByte(stream); }
Basecase - Just loop
for (i=0; i<totalBytes; i++) { }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Dataview
Custom
Basecase - Just loop

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 6 years ago)

User agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/66.0.3359.139 Safari/537.36

Browser/OS: Chrome 66 on Windows 7

View result in a separate tab

Test name	Executions per second
Dataview	2.7 Ops/sec
Custom	1.5 Ops/sec
Basecase - Just loop	14.7 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested.

**Benchmark Definition JSON**

The provided JSON defines a benchmark with three test cases:

* **Dataview vs Custom - Read uint8**: This is the main benchmark, which compares the performance of two approaches: using `DataView` (a built-in JavaScript object for reading/writing binary data) and using a custom function (`readUnsignedByte`) to read unsigned bytes from a Uint8Array buffer.

**Benchmark Preparation Code**

The preparation code sets up the test environment:

1. Creates an ArrayBuffer with a total size of 1024 KB.
2. Creates a DataView object on top of the buffer, allowing for reading/writing binary data.
3. Fills the buffer with random unsigned bytes using `Math.random()`.

**Individual Test Cases**

The three test cases are defined in separate objects:

* **Dataview**: This test case uses the `DataView` object to read the unsigned bytes from the buffer. The benchmark definition code is identical to the preparation code, but it's executed inside a loop to measure performance.
* **Custom**: This test case uses the custom function (`readUnsignedByte`) to read the unsigned bytes from the buffer. The benchmark definition code reads the bytes using this function and returns the value as an integer.
* **Basecase - Just loop**: This test case is a simple benchmark that just loops through the entire buffer without doing anything meaningful. It's likely used as a baseline for comparison.

**Libraries and Special Features**

The custom `readUnsignedByte` function uses a library called `Uint8Array`, which is a built-in JavaScript object for representing arrays of unsigned 8-bit integers. The purpose of this library is to provide a convenient way to work with binary data in JavaScript.

There are no special features or syntax used in the benchmark that would require advanced knowledge of JavaScript.

**Options Compared**

The two main options being compared are:

1. **Using `DataView`**: This approach provides direct access to the underlying buffer, allowing for efficient reading/writing of binary data.
2. **Using a custom function (`readUnsignedByte`)**: This approach creates an abstraction layer on top of the Uint8Array object, which may incur additional overhead due to function call and parameter passing.

**Pros and Cons**

* Using `DataView`:
	+ Pros: direct access to the buffer, efficient reading/writing of binary data.
	+ Cons: may not be as readable or maintainable as using a custom function.
* Using a custom function (`readUnsignedByte`):
	+ Pros: more readable/maintainable code, easier to understand the logic behind the benchmark.
	+ Cons: potential overhead due to function call and parameter passing.

**Other Alternatives**

Some alternative approaches could be considered:

1. **Using `Uint8Array.prototype[Symbol.iterator]()`**: Instead of using a custom function or DataView, you could use the iterator protocol to iterate over the Uint8Array object.
2. **Using a third-party library**: Depending on the specific requirements and constraints of the benchmark, other libraries like `buffer` or `binarysearch` might be used as alternatives.

Keep in mind that these alternatives would likely change the nature of the benchmark significantly, so it's essential to carefully evaluate their trade-offs before making any changes.

Related benchmarks:

Dataview vs Custom - Read uint8 (version: 1)

Comparing performance of: Dataview vs Custom vs Basecase - Just loop

Created: 7 years ago by: Registered User

Jump to the latest result

Dataview

Custom

Basecase - Just loop

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):