Benchmark: instanceOf-bitwise

Script Preparation code:

class X {    
    
}

class Y extends X {    
}

var globalX = X;
var y = new Y();

var types = {
  'A': 1,
  'B': 2
}

class A {
  constructor() {
    this.type = types.A;
  }
}

class B extends A {
  constructor() {
    super();
    this.type = types.A | types.B;
  }
}

var b = new B();

Tests:

instanceOf
y instanceof globalX;
flag check
b.type & types.A;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
instanceOf
flag check

Fastest: N/A

Slowest: N/A

Autogenerated LLM Sumamry (model llama3.2:3b, generated 18 days ago):

LLMs can make mistakes. Check important info.

Let's break down what's being tested in the provided JSON benchmark definition and test cases.

**Benchmark Definition:**

The test case measures the performance of two different approaches:

1. `y instanceof globalX;`
2. `b.type & types.A;`

These tests are designed to compare the execution speed of these two expressions.

**Options compared:**

The two options being compared are:

A) Using the `instanceof` operator with a bitwise comparison (`globalX`)
B) Using a bitwise AND operation (`&`) on flags (`types.A`)

**Pros and Cons:**

1. **Using `instanceof` operator with a bitwise comparison (Option A):**
	* Pros:
		+ More readable and self-explanatory code
		+ Easier to understand the intent of the test
	* Cons:
		+ May be slower due to the extra overhead of the `instanceof` operator
		+ Can lead to less efficient use of CPU resources if not optimized properly
2. **Using a bitwise AND operation (Option B):**
	* Pros:
		+ Often faster than using `instanceof`
		+ Can lead to more direct and efficient use of CPU resources
	* Cons:
		+ Less readable and may require additional understanding of bitwise operations
		+ May not be as clear about the intent of the test

**Library:**

The test case uses the built-in JavaScript `instanceof` operator, which is a part of the ECMAScript standard. The purpose of this operator is to check if an object is an instance of a given constructor function.

**Special JS feature or syntax:**

There are no special JavaScript features or syntaxes used in this benchmark definition.

**Other considerations:**

When evaluating performance-critical code, it's essential to consider factors such as:

* Cache locality and memory access patterns
* Branch prediction and instruction-level parallelism
* Optimizations specific to the target architecture

In this case, the test may want to consider using specialized profiling tools or techniques, such as:

* Compiler optimization flags
* Cache-aware data structures
* Instruction-level optimizations (e.g., SIMD instructions)

**Alternatives:**

If you need to measure performance for similar scenarios, here are some alternative benchmarks you could use:

1. **Array operations:** Test the performance of different array methods, such as `forEach`, `map`, or `reduce`.
2. **String processing:** Measure the speed of string concatenation, substring extraction, or regular expression matching.
3. **Object iteration:** Compare the performance of iterating over objects using `for...in` or `for...of`.

Keep in mind that each test should be designed to evaluate specific aspects of performance and optimization.

Latest run results:

Run details: (Test run date: 3 years ago)

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/92.0.4515.159 Safari/537.36

Browser/OS: Chrome 92 on Linux

View result in a separate tab

Test name	Executions per second
instanceOf	6824499.0 Ops/sec
flag check	6988771.0 Ops/sec

Related benchmarks:

instanceOf-bitwise (version: 1)

Comparing performance of: instanceOf vs flag check

Created: 3 years ago by: Registered User

Jump to the latest result

instanceOf

flag check

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Sumamry (model llama3.2:3b, generated 18 days ago):