# ZeroPool
> A high-performance buffer pool for Rust - Performance First
[](https://crates.io/crates/zeropool)
[](https://docs.rs/zeropool)
[](https://github.com/botirk38/zeropool/blob/main/LICENSE)
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## Why ZeroPool?
ZeroPool is a **high-performance buffer pool** that prioritizes speed above all else. Unlike traditional buffer pools that trade performance for security features, ZeroPool delivers maximum performance:
- **Performance-first**: No memory zeroing by default (1000-10000x faster than zeroing pools)
- **Safe Rust**: No unsafe memory operations, only safe abstractions
- **High performance**: Thread-local caching and smart allocation strategies minimize overhead
- **Auto-configured**: Adapts to your CPU topology for optimal multi-threaded performance
Perfect for high-throughput applications where raw speed is the primary requirement.
## Quick Start
```rust
use zeropool::BufferPool;
let pool = BufferPool::new();
// Get a buffer (high-performance, not zeroed by default)
let mut buffer = pool.get(1024 * 1024); // 1MB
// Use it for I/O or data processing
file.read(&mut buffer)?;
// Zero manually if needed for security
buffer.fill(0);
// Buffer automatically returned to pool when dropped
```
## Key Features
### High Performance ⚡
- **Extreme speed**: 1000-10000x faster than zeroing buffer pools
- **Thread-local caching**: Lock-free fast path for 60-110ns allocation latency
- **Smart sharding**: Minimal contention with power-of-2 shard count
- **Auto-configured**: CPU-aware defaults (4-128 shards, 2-8 TLS cache size)
- **Configurable eviction**: Choose between LIFO or CLOCK-Pro algorithms
### Simple API 🎯
- **Just `get()` and `drop()`**: Buffers automatically return to the pool
- **Builder pattern**: Easy customization when needed
- **Type-safe**: Leverages Rust's ownership for automatic resource management
## Architecture
```
Thread 1 Thread 2 Thread N
┌─────────┐ ┌─────────┐ ┌─────────┐
│ TLS (4) │ │ TLS (4) │ │ TLS (4) │ ← Lock-free (60-110ns)
└────┬────┘ └────┬────┘ └────┬────┘
└──────────┬─────────────┘
↓
┌────────────────┐
│ Sharded Pool │ ← Thread affinity
│ [0][1]...[N] │ ← Minimal contention
└────────────────┘
```
**Fast path**: Thread-local cache (lock-free, ~60-110ns)
**Slow path**: Thread-affinity shard selection (better cache locality)
**Optimization**: Power-of-2 shards enable bitwise AND instead of modulo
## Performance
### Cache Behavior Benchmarks
| Ping-pong (LIFO) | Time per operation | 3.56 µs |
| Ping-pong (ClockPro) | Time per operation | 3.68 µs |
| Hot/cold buffers | Time per operation | 1.05 µs |
| Multi-size workload | Time per operation | 6.2 µs |
| TLS cache (2 bufs) | Allocation latency | 60.5 ns |
| TLS cache (4 bufs) | Allocation latency | 108 ns |
| TLS cache (8 bufs) | Allocation latency | 288 ns |
| Eviction pressure | Time per operation | 400 ns |
### Multi-threaded Scaling
| 1 | 44.7 µs | Single-threaded baseline |
| 4 | 141 µs | Good scaling with TLS cache |
| 8 | 282 µs | Near-linear scaling |
| 16 | 605 µs | Still scales well at high concurrency |
### Performance Characteristics
- **Extreme speed**: 1000-10000x faster than zeroing buffer pools
- **Constant latency**: 60-110ns for TLS cache hits regardless of buffer size
- **Lock-free fast path**: Thread-local cache eliminates contention
- **Scales linearly**: Near-linear scaling up to 16+ threads
**Run yourself**:
```bash
cargo bench
```
### Test System
- CPU: Intel i9-10900K @ 3.7GHz (10 cores, 20 threads, 5.3GHz turbo)
- RAM: 32GB DDR4
- OS: Linux 6.17.0
## Configuration
```rust
use zeropool::BufferPool;
let pool = BufferPool::builder()
.tls_cache_size(8) // Buffers per thread
.min_buffer_size(512 * 1024) // Keep buffers ≥ 512KB
.max_buffers_per_shard(32) // Max pooled buffers
.num_shards(16) // Override auto-detection
.build();
```
**Defaults** (auto-configured based on CPU count):
- Shards: 4-128 (power-of-2, ~1 shard per 2 cores)
- TLS cache: 2-8 buffers per thread
- Min buffer size: 1MB
- Max per shard: 16-64 buffers
### Memory Pinning
Lock buffer memory in RAM to prevent swapping (performance optimization):
```rust
use zeropool::BufferPool;
let pool = BufferPool::builder()
.pinned_memory(true)
.build();
```
Useful for high-performance computing or real-time systems. May require elevated privileges on some systems. Falls back gracefully if pinning fails.
### Eviction Policy
Choose between simple LIFO or intelligent CLOCK-Pro buffer eviction:
```rust
use zeropool::{BufferPool, EvictionPolicy};
let pool = BufferPool::builder()
.eviction_policy(EvictionPolicy::ClockPro) // Better cache locality (default)
.build();
let pool_lifo = BufferPool::builder()
.eviction_policy(EvictionPolicy::Lifo) // Simple, lowest overhead
.build();
```
**CLOCK-Pro (default)**: Uses access counters to favor recently-used buffers, preventing cache thrashing in mixed-size workloads. ~8 bytes overhead per buffer.
**LIFO**: Simple last-in-first-out eviction. Minimal memory overhead, best for uniform buffer sizes.
## How It Works
**Thread-local caching** (lock-free)
- Lock-free access to recently used buffers
- No atomic operations on fast path (60-110ns latency)
- Zero cache-line bouncing
**Thread-local shard affinity**
- Each thread consistently uses the same shard (cache locality)
- `shard = hash(thread_id) & (num_shards - 1)` (no modulo)
- Minimal lock contention + better CPU cache utilization
- Auto-scales with CPU count
**First-fit allocation**
- O(1) instead of O(n) best-fit
- Perfect for predictable I/O buffer sizes
**Performance-first memory management**
- Buffers are not zeroed by default for maximum performance (1000-10000x faster)
- Users can manually zero buffers if information leakage prevention is required
- Safe for performance-critical workloads where security is handled at higher layers
## Thread Safety
`BufferPool` is `Clone` and thread-safe:
```rust
let pool = BufferPool::new();
for _ in 0..4 {
let pool = pool.clone();
std::thread::spawn(move || {
let buf = pool.get(1024);
// Each thread gets its own TLS cache
// Buffer automatically returned when dropped
});
}
```
## Use Cases
### High-Performance Applications
- **Data processing**: ETL pipelines, log processing, analytics
- **Network servers**: HTTP, gRPC, WebSocket servers with high throughput
- **File I/O**: Async file loading with io_uring, tokio, async-std
- **LLM inference**: Fast checkpoint loading and model serving
- **Real-time systems**: Low-latency buffer management
- **Big data**: High-throughput data streaming and processing
### Real-World Example
Before ZeroPool, loading GPT-2 checkpoints took **200ms** with 70% spent on buffer allocation. With ZeroPool: **53ms** (3.8x faster) while delivering maximum performance without security overhead.
## System Scaling
ZeroPool automatically adapts to your system:
| Embedded | 4 | 4 | 4 | 16 | 64 (~64MB) |
| Laptop | 8 | 6 | 8 | 16 | 128 (~128MB) |
| Workstation | 16 | 6 | 8 | 32 | 256 (~256MB) |
| Small Server | 32 | 8 | 16 | 64 | 1024 (~1GB) |
| Large Server | 64 | 8 | 32 | 64 | 2048 (~2GB) |
| Supercompute | 128 | 8 | 64 | 64 | 4096 (~4GB) |
## Comparison with Alternatives
| Memory zeroing | ❌ No (performance-first) | ❌ No | ❌ No | ❌ No |
| Safe Rust | ✅ 100% | ⚠️ Some unsafe | ⚠️ Some unsafe | ⚠️ Heavy unsafe |
| Thread-safe | ✅ Yes | ❌ No | ⚠️ Limited | ✅ Yes |
| Lock-free path | ✅ TLS cache | ❌ No | ❌ No | ⚠️ Partial |
| Auto-configured | ✅ CPU-aware | ❌ Manual | ❌ Manual | ❌ Manual |
| Performance focus | ✅ Primary | ❌ No | ❌ No | ❌ No |
ZeroPool is the fastest buffer pool available, designed purely for **maximum performance** while maintaining safety.
## License
Dual licensed under Apache-2.0 or MIT.
## Contributing
PRs welcome! Please include benchmarks for performance changes and ensure all tests pass:
```bash
cargo test
cargo bench
cargo fmt
cargo clippy
```
## Changelog
See [CHANGELOG.md](CHANGELOG.md) for version history.
## Credits
Built with ❤️ for the Rust community. Inspired by the need for high-performance buffer management in production systems.