Benchmark: branchfuncofbranchlessmapfunc

Script Preparation code:

var branchlessMap = [function(){return "error"}, function(a, b){return a - b ^ a}, function(a, b) {return a ** b}];
var global;
var thing = 50;

Tests:

branch
thing *= 2; if(thing > 100) { global = thing - 100 ^ thing; } else { global = "error"; } if(thing < 100) { global = thing ** 100; } else { global = "error"; }
branchless map
thing *= 2; global = branchlessMap[(thing > 100) * 1](thing); global = branchlessMap[(thing < 100) * 2](thing);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
branch
branchless map

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

This benchmark does not have any results yet. Be the first one to run it!

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

LLMs can make mistakes. Check important info.

I'll break down the provided benchmark definition and test cases to explain what's being tested, compared, and their pros and cons.

**Benchmark Definition:**

The benchmark is defined by two scripts: `Script Preparation Code` and `Html Preparation Code`. The script preparation code defines a JavaScript array called `branchlessMap`, which contains three functions:

1. `return "error"`: a simple function that returns the string "error".
2. `return a - b ^ a`: a function that takes two arguments, performs subtraction and bitwise XOR on them, and returns the result.
3. `return a ** b`: a function that raises the first argument to the power of the second.

The script preparation code also declares a global variable `global` and assigns it an initial value of 50 using the `var thing = 50;` statement.

**Test Cases:**

There are two test cases:

1. "branch":
	* The benchmark definition is a JavaScript expression that checks if the value of `thing` is greater than 100. If true, it sets `global` to the result of `(thing - 100) ^ thing`. Otherwise, it sets `global` to `"error"`.
2. "branchless map":
	* The benchmark definition uses the `branchlessMap` array to call two functions based on a conditional statement.
		+ If `thing > 100`, it calls `branchlessMap[(thing > 100) * 1](thing)`.
		+ If `thing < 100`, it calls `branchlessMap[(thing < 100) * 2](thing)`.

**Comparison:**

The two test cases compare the performance of conditional statements (with branching) versus using an array-based approach to select functions based on conditions (`branchless map`).

**Pros and Cons:**

**Branching (Test Case "branch")**

Pros:

* Easy to understand and maintain.
* Can be optimized by minimizing branch prediction errors.

Cons:

* May lead to slower performance due to branching.
* Can result in higher overhead for conditional checks.

**Branchless Map (Test Case "branchless map")**

Pros:

* Can lead to better performance due to reduced branching.
* Avoids the overhead of explicit conditional checks.

Cons:

* Requires a more complex understanding of array indexing and function selection.
* May be less maintainable due to its abstract nature.

**Library:**

The `branchlessMap` array is not a standard library, but rather a custom implementation by the benchmark creator. It provides an alternative way to select functions based on conditions without using branching statements.

**Special JS Feature/Syntax:**

There are no special JavaScript features or syntax used in this benchmark. The code uses standard JavaScript syntax and features like bitwise XOR (`^`) and exponentiation (`**`).

**Alternatives:**

Other alternatives for the "branchless map" approach could include:

1. Using a lookup table or a hash-based approach to quickly select functions.
2. Employing other array-based data structures, such as `Map` objects or `Set`s, to store function mappings.
3. Utilizing compiler optimizations like inlining or function selection at compile-time.

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

Related benchmarks:

branchfuncofbranchlessmapfunc (version: 0)

idk

Comparing performance of: branch vs branchless map

Created: 4 years ago by: Guest

Jump to the latest result

branch

branchless map

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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