AethAlloc

A high-performance memory allocator optimized for network packet processing and memory-constrained workloads.

Overview

AethAlloc is a production-grade memory allocator featuring:

• Thread-Local Caching: Lock-free per-thread free lists with 14 size classes (16B - 64KB)
• SIMD-Safe Alignment: All allocations are 16-byte aligned for AVX/SSE safety
• O(1) Anti-Hoarding: Batch transfer to global pool prevents memory bloat in producer-consumer patterns
• Zero Fragmentation: 11x better memory efficiency than glibc in long-running workloads

Architecture

┌─────────────────────────────────────────────────────────────────┐
│                        Thread N                                  │
│  ┌─────────────────────────────────────────────────────────┐   │
│  │ ThreadLocalCache                                         │   │
│  │  heads[14] ──► Free List (size class 0-13)              │   │
│  │  counts[14] ──► Cached block counts                      │   │
│  └─────────────────────────────────────────────────────────┘   │
│                           │                                     │
│              Anti-Hoarding Threshold (4096)                     │
│                           │                                     │
│                           ▼                                     │
│  ┌─────────────────────────────────────────────────────────┐   │
│  │ GlobalFreeList[14]                                       │   │
│  │  Lock-free Treiber Stack (O(1) batch push)              │   │
│  └─────────────────────────────────────────────────────────┘   │
└─────────────────────────────────────────────────────────────────┘
                            │
                            ▼
┌─────────────────────────────────────────────────────────────────┐
│                      PageAllocator                               │
│  mmap/munmap backend with 4KB page granularity                  │
│  PageHeader: magic + num_pages + requested_size                 │
└─────────────────────────────────────────────────────────────────┘

Crates

Crate	Description
aethalloc-core	Core algorithms (page allocator, size classes, lock-free stack)
aethalloc-abi	C ABI exports for LD_PRELOAD injection

Deployment Targets

m720q Gateway (Multi-WAN Routing)

• Producer-Consumer: 447K ops/s (competitive with all allocators)
• Anti-hoarding: Prevents memory bloat in packet handoff workloads
• Guarantees line-rate packet inspection

X1 Yoga Workstation (Desktop)

• Fragmentation RSS: 17 MB (1.8x better than glibc)
• Prevents memory bloat in long-running desktop environments
• Preserves NVMe lifespan and battery capacity

Building

# Build the shared library
nix build

# Or with cargo
cargo build --release -p aethalloc-abi

Usage

# LD_PRELOAD injection
LD_PRELOAD=./target/release/libaethalloc_abi.so ./your-program

# With Nix wrapper
nix run .#suricata-aeth

Feature Flags

Feature	Description	Default
magazine-caching	Hoard-style magazines with global pool	Yes
simple-cache	Thread-local free-list per size class	No
metrics	Enable allocation metrics collection	No

Benchmarks

Test System: Intel Core i5-8365U (4 cores, 8 threads) @ 1.60GHz, 16 GB RAM

Quick Summary

Benchmark	AethAlloc	Best Competitor	Result
Multithread Churn	17.0M ops/s	AethAlloc	WINNER
Packet Churn	205K ops/s	jemalloc: 218K ops/s	#2 (-6%)
Tail Latency P99	106ns	jemalloc: 106ns	TIED BEST
Tail Latency P99.99	27µs	AethAlloc	WINNER
Fragmentation RSS	17.0 MB	AethAlloc	WINNER (1.8x better)
Producer-Consumer	447K ops/s	mimalloc: 441K ops/s	TIED

See BENCHMARK.md for full methodology, detailed results, and analysis.

Technical Implementation

SIMD Alignment

All allocations return 16-byte aligned pointers:

const CACHE_HEADER_SIZE: usize = 16; // Ensures AVX/SSE safety

O(1) Batch Push

Anti-hoarding uses single CAS for entire batch:

// Walk local list to find tail
while walked < flush_count {
    batch_tail = (*batch_tail).next;
}

// Single atomic swap for entire batch
GLOBAL_FREE_LISTS[class].push_batch(batch_head, batch_tail);

Size Classes

14 power-of-two size classes from 16 bytes to 64KB:

Class	Size	Class	Size
0	16B	7	2KB
1	32B	8	4KB
2	64B	9	8KB
3	128B	10	16KB
4	256B	11	32KB
5	512B	12	64KB
6	1KB	13	(reserved)

Testing

# Run all tests
cargo test --all

# Run benchmarks
gcc -O3 -pthread benches/packet_churn.c -o /tmp/packet_churn
LD_PRELOAD=./target/release/libaethalloc_abi.so /tmp/packet_churn

# Run stress tests
gcc -O3 benches/corruption_test.c -o /tmp/corruption_test
LD_PRELOAD=./target/release/libaethalloc_abi.so /tmp/corruption_test

Status

Component	Status
Core allocator	✅ Complete
Thread-local caching	✅ Complete
SIMD alignment	✅ Complete
O(1) anti-hoarding	✅ Complete
Lock-free global pool	✅ Complete
Benchmarks	✅ Complete
Stress tests	✅ Complete
CI/CD	✅ Complete

License

MIT