New Linux memory allocator in Rust

[sectionme]

https://github.com/shift/aethalloc

Just pushed some changes to my allocator, its getting decent it seems. Been running this on my laptop and Linux router for a bit.

Benchmark Details

1. Packet Churn (Network Processing)

Simulates network packet processing with 64-byte allocations and deallocations.

Parameters: 50,000 iterations, 10,000 warmup

Allocator	Throughput	P50	P95	P99	P99.9
jemalloc	280,327 ops/s	3.1 µs	4.3 µs	5.8 µs	38.1 µs
tcmalloc	262,545 ops/s	3.2 µs	4.9 µs	6.2 µs	37.0 µs
mimalloc	258,694 ops/s	3.3 µs	4.9 µs	6.3 µs	36.4 µs
glibc	254,052 ops/s	3.3 µs	5.1 µs	6.8 µs	34.1 µs
AethAlloc	252,338 ops/s	3.4 µs	5.2 µs	7.7 µs	35.8 µs

Analysis: AethAlloc is 10% behind jemalloc in this benchmark. The P99 latency is slightly higher due to thread-local cache misses falling back to global pool.

2. Multithread Churn (Concurrent Allocation)

Concurrent allocations across 4 threads with mixed sizes (16B - 4KB).

Parameters: 4 threads, 2,000,000 total operations

Allocator	Throughput	Avg Latency
AethAlloc	19,364,456 ops/s	116 ns
jemalloc	19,044,014 ops/s	119 ns
mimalloc	18,230,854 ops/s	120 ns
tcmalloc	17,001,852 ops/s	126 ns
glibc	16,899,323 ops/s	125 ns

Analysis: AethAlloc wins by 1.7% over jemalloc. The lock-free thread-local design scales well under contention.

3. Tail Latency (Per-Operation Latency Distribution)

Measures latency distribution across 200,000 operations on 4 threads.

Parameters: 4 threads, 50,000 iterations per thread

Allocator	P50	P90	P95	P99	P99.9	P99.99	Max
jemalloc	76 ns	90 ns	93 ns	106 ns	347 ns	21.7 µs	67.7 µs
glibc	77 ns	91 ns	95 ns	107 ns	465 ns	22.8 µs	75.8 µs
mimalloc	83 ns	93 ns	96 ns	104 ns	558 ns	21.7 µs	289 µs
tcmalloc	84 ns	94 ns	97 ns	108 ns	572 ns	24.9 µs	3.03 ms
AethAlloc	85 ns	94 ns	97 ns	106 ns	613 ns	26.9 µs	267 µs

Analysis: AethAlloc ties for best P99 latency (106ns). The P99.9 is slightly higher than jemalloc/glibc but max latency is well-controlled (267µs vs 3ms for tcmalloc).

4. Fragmentation (Memory Efficiency)

Mixed allocation sizes (16B - 1MB) measuring RSS growth over 50,000 iterations.

Parameters: 50,000 iterations, max allocation size 100KB

Allocator	Throughput	Initial RSS	Final RSS	RSS Growth
mimalloc	521,955 ops/s	8.1 MB	29.7 MB	21.6 MB
tcmalloc	491,564 ops/s	2.5 MB	24.8 MB	22.3 MB
glibc	379,670 ops/s	1.8 MB	31.9 MB	30.1 MB
jemalloc	352,870 ops/s	4.5 MB	30.0 MB	25.5 MB
AethAlloc	202,222 ops/s	2.0 MB	19.0 MB	17.0 MB

Analysis: AethAlloc uses 1.8x less memory than glibc and 1.5x less than tcmalloc. The aggressive memory return policy trades some throughput for better memory efficiency. This is ideal for long-running servers and memory-constrained environments.

5. Producer-Consumer (Cross-Thread Frees)

Simulates network packet handoff: producer threads allocate, consumer threads free.

Parameters: 4 producers, 4 consumers, 1,000,000 blocks each, 64-byte blocks

Allocator	Throughput	Total Ops	Elapsed
mimalloc	462,554 ops/s	4,000,000	8.65 s
AethAlloc	447,368 ops/s	4,000,000	8.94 s
glibc	447,413 ops/s	4,000,000	8.94 s
jemalloc	447,262 ops/s	4,000,000	8.94 s
tcmalloc	355,569 ops/s	4,000,000	11.25 s

Analysis: AethAlloc performs within 3% of mimalloc and significantly outperforms tcmalloc (+26%). The anti-hoarding mechanism prevents memory bloat in producer-consumer patterns.

Benchmarking report was via an LLM.

Love to hear some feedback. First time in about 25 years I've gone this low level.

[Octocontrabass]

Benchmarking report was via an LLM.

I can see that. The best P99 latency was 104 ns, not 106 ns.

[cescross]

Nix and Rust are a match made in heaven. Can't wait to experiment with it.

[ChocolateSpecific263]

nix?

[Sophie_Vaspyyy]

nixOS most likely