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V8 garbage collection vs out-of-scope access cost (v8 optimization buster)
(version: 0)
Comparing performance of:
garbage collection vs out of scope access
Created:
4 years ago
by:
Guest
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Script Preparation code:
var k1 = 0, k2 = 1, k3 = 2; var k = () => { eval(''); k1 = k2 + k3; k2 = k1 + k3; k1 = k2 + k3; k3 = k1 + k1; return k1 + k2 + k3; }; var _k = () => { eval(''); let _k1 = 0, _k2 = 1, _k3 = 2; _k1 = _k2 + _k3; _k2 = _k1 + _k3; _k1 = _k2 + _k3; _k3 = _k1 + _k1; return _k1 + _k2 + _k3; }
Tests:
garbage collection
_k();
out of scope access
k();
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
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Test case name
Result
garbage collection
out of scope access
Fastest:
N/A
Slowest:
N/A
Latest run results:
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Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's dive into explaining what is tested on the provided JSON that represents the benchmark. The test case measures the performance difference between two approaches: **1. Garbage Collection (GC)**: In this approach, the variable `k` is declared as an immediately invoked function expression (IIFE) using the arrow function syntax (`() => { ... }`). The function body contains a series of assignments and arithmetic operations. Since `k` is an IIFE, it has its own scope, and any variables assigned to `k` within the function will not affect the outer scope. When the function returns, the scope is closed, and the garbage collector (GC) is triggered. The test measures how long it takes for the GC to kick in when accessing out-of-scope variables (`k1`, `k2`, `k3`) after the function has returned. **Pros of using IIFE:** * Encapsulation: The inner scope is isolated from the outer scope. * Memory management: The garbage collector can more efficiently clean up memory by identifying and removing dead variables. **Cons of using IIFE:** * Complexity: IIFEs can be harder to read and understand due to their nested scope. * Overhead: Creating an IIFE involves function creation and execution, which can lead to additional overhead. **2. Out-of-Scope Access (SOA)**: In this approach, the variable `_k` is declared as a regular function using the traditional syntax (`function () { ... }`). The function body contains similar arithmetic operations as before. However, unlike the IIFE approach, `k1`, `k2`, and `k3` are assigned values in the outer scope, making them accessible to the inner scope. The test measures how long it takes for the garbage collector to kick in when accessing out-of-scope variables (`_k1`, `_k2`, `_k3`) after the function has returned. **Pros of using traditional syntax:** * Simplicity: Regular functions are often easier to read and understand. * Less overhead: Creating a regular function is less complex than an IIFE. **Cons of using traditional syntax:** * Global scope: Variables in the outer scope can pollute the global namespace. * Memory management: The garbage collector may have difficulty identifying and removing dead variables due to their global presence. The test also uses `eval()` which is a function that parses and executes a string as JavaScript code. This feature has been deprecated since ECMAScript 2015 (ES6) and should not be used in production code. Other alternatives for the GC approach could include: * Using `let` or `const` declarations with block scope to avoid polluting the global namespace. * Implementing a manual memory management system, which can be error-prone and lead to performance issues if not implemented correctly. For the SOA approach, alternative options could include: * Using a different data structure, such as an object or array, to avoid polluting the global namespace. * Implementing a lazy loading mechanism for out-of-scope variables. Keep in mind that these alternatives may change the functionality of the code and should be carefully evaluated before making changes.
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V8 garbage collection vs out-of-scope access cost
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