1. EachPod

Memory Allocation Strategies with Zig

Author
Pragmatic AI Labs
Published
Tue 18 Feb 2025
Episode Link
podcast.paiml.com

Zig's Memory Management Philosophy

  • Explicit and transparent memory management
  • Runtime error detection vs compile-time checks
  • No hidden allocations
  • Must handle allocation errors explicitly using try/defer/ensure
  • Runtime leak detection capability

Comparison with C and Rust

C Differences

  • Safer than C due to explicit memory handling
  • No "foot guns" or easy-to-create security holes
  • No forgotten free() calls
  • Clear memory ownership model

Rust Differences

  • Rust: Compile-time ownership and borrowing rules
    • Single owner for memory
    • Automatic memory freeing
    • Built-in safety with performance trade-off
  • Zig: Runtime-focused approach
    • Explicit allocators passed around
    • Memory management via defer
    • No compile-time ownership restrictions
    • Runtime leak/error checking

Four Types of Zig Allocators

General Purpose Allocator (GPA)

  • Tracks all allocations
  • Detects leaks and double-frees
  • Like a "librarian tracking books"
  • Most commonly used for general programming

Arena Allocator

  • Frees all memory at once
  • Very fast allocations
  • Best for temporary data (e.g., JSON parsing)
  • Like "dumping LEGO blocks"

Fixed Buffer Allocator

  • Stack memory only, no heap
  • Fixed size allocation
  • Ideal for embedded systems
  • Like a "fixed size box"

Page Allocator

  • Direct OS memory access
  • Page-aligned blocks
  • Best for large applications
  • Like "buying land and subdividing"

Real-World Performance Comparisons

Binary Size

  • Zig "Hello World": ~300KB
  • Rust "Hello World": ~1.8MB

HTTP Server Sizes

  • Zig minimal server (Alpine Docker): ~300KB
  • Rust minimal server (Scratch Docker): ~2MB

Full Stack Example

  • Zig server with JSON/SQLite: ~850KB
  • Rust server with JSON/SQLite: ~4.2MB

Runtime Characteristics

  • Zig: Near-instant startup, ~3KB runtime
  • Rust: Runtime initialization required, ~100KB runtime size
  • Zig offers optional runtime overhead
  • Rust includes mandatory memory safety runtime

The episode concludes by suggesting Zig as a complementary tool alongside Rust, particularly for specialized use cases requiring minimal binary size or runtime overhead, such as embedded systems development.


🔥 Hot Course Offers:

🚀 Level Up Your Career:

Learn end-to-end ML engineering from industry veterans at PAIML.COM

Share to: