zeptoclaw 0.7.2

Ultra-lightweight personal AI assistant
Documentation
# ZeptoClaw Performance Guide

This document covers performance characteristics, benchmarks, and optimization tips for ZeptoClaw.

## Quick Facts

| Metric | Value |
|--------|-------|
| **Memory per user** | ~12 KB |
| **Max concurrent users** | 1000+ on $5 VPS |
| **Throughput** | 4,000+ msg/s |
| **Latency (p99)** | <1ms |
| **Binary size** | ~5 MB |
| **Cold start** | <50ms |

## Benchmark Results

See [BENCHMARK_RESULTS.md](./BENCHMARK_RESULTS.md) for detailed benchmark data.

### Summary

```
100 users   → 5 MB RAM  → 93 msg/s
500 users   → 10 MB RAM → 466 msg/s
1000 users  → 12 MB RAM → 932 msg/s
5000 users  → ~60 MB RAM (projected)
```

## Why Rust Enables This Performance

### 1. Memory Efficiency

**Rust (Tokio task):**
```rust
// ~4KB stack per concurrent user
tokio::spawn(async move {
    handle_user(connection).await
});
```

**Go (goroutine):**
```go
// ~1MB stack per concurrent user
go func() {
    handleUser(connection)
}()
```

**Python (thread):**
```python
# ~50MB per concurrent user
threading.Thread(target=handle_user).start()
```

**Result:** Rust uses **250x less memory** than Go per user.

### 2. No GC Pauses

- **Go:** GC pauses cause latency spikes under load
- **Python:** GIL limits true parallelism
- **Rust:** Zero-cost abstractions, deterministic performance

### 3. Zero-Copy Architecture

```rust
// Message passing without cloning
tx.send(Arc::new(message)).await?;

// Lock-free channels
let (tx, rx) = tokio::sync::mpsc::channel(1000);
```

## Deployment Scenarios

### Personal Use (1-10 users)
```bash
# Runs comfortably on any hardware
# Raspberry Pi 4, old laptop, etc.
zeptoclaw gateway
```

### Small Team (10-100 users)
```bash
# $5/month DigitalOcean droplet
# 512MB RAM, 1 vCPU
zeptoclaw gateway --config production.toml
```

### Startup (100-1000 users)
```bash
# Still fits on $5 VPS
# Or upgrade to $10 for headroom
# 1GB RAM, 1 vCPU
```

### Enterprise (1000-10000 users)
```bash
# $40/month dedicated
# 4GB RAM, 2 vCPUs
# Horizontal scaling ready
```

## Performance Tuning

### 1. Release Build

Always use release builds for production:

```bash
cargo build --release
```

Profile in `Cargo.toml`:
```toml
[profile.release]
opt-level = "z"     # Optimize for size
lto = true          # Link-time optimization
codegen-units = 1   # Single codegen unit
strip = true        # Strip symbols
panic = "abort"     # Abort on panic
```

### 2. Session Pruning

For long-running instances, limit session history:

```rust
// In your config
max_session_messages = 100
session_ttl_hours = 24
```

### 3. Connection Pooling

The HTTP client already uses connection pooling:

```rust
let client = reqwest::Client::builder()
    .pool_max_idle_per_host(100)
    .build()?;
```

### 4. Message Buffer Size

Adjust based on your load:

```rust
// For high-throughput scenarios
let bus = MessageBus::with_buffer_size(10_000);
```

## Monitoring Performance

### Built-in Benchmark

```bash
# Build benchmark tool
cargo build --bin benchmark --release

# Run benchmark
./target/release/benchmark --users 100 --duration 30 --memory-profile
```

### System Metrics

Monitor these in production:

```bash
# Memory usage
ps -o rss= -p $(pgrep zeptoclaw)

# CPU usage
top -pid $(pgrep zeptoclaw)

# Open connections
lsof -p $(pgrep zeptoclaw) | grep ESTABLISHED | wc -l
```

### Log Analysis

Enable structured logging:

```bash
RUST_LOG=info zeptoclaw gateway 2>&1 | jq '. | {timestamp, level, fields}'
```

## Bottlenecks and Solutions

| Bottleneck | Symptom | Solution |
|------------|---------|----------|
| LLM API rate limits | Slow responses | Implement caching |
| Disk I/O | Session save lag | Use tmpfs for sessions |
| Memory growth | OOM crashes | Enable session pruning |
| CPU saturation | High load | Scale horizontally |

## Comparison with Other Solutions

### vs. Python (FastAPI + Celery)

| Aspect | Python | ZeptoClaw |
|--------|--------|-----------|
| 1000 users RAM | 4 GB | 12 MB |
| Throughput | 100 msg/s | 932 msg/s |
| Cold start | 2s | 50ms |
| Deployment | Complex | Single binary |

### vs. Go (Gin + Goroutines)

| Aspect | Go | ZeptoClaw |
|--------|-----|-----------|
| 1000 users RAM | 1 GB | 12 MB |
| GC pauses | 10-100ms | None |
| Binary size | 15 MB | 5 MB |
| Throughput | Similar | Similar |

### vs. Managed Services

| Service | 1000 users/month | Pros/Cons |
|---------|------------------|-----------|
| OpenAI Assistants | ~$200 | Easy, but expensive |
| Google Dialogflow | ~$300 | Enterprise features |
| **ZeptoClaw** | **$5** | Self-hosted, private |

## Optimization Checklist

Before deploying to production:

- [ ] Use release build (`--release`)
- [ ] Set appropriate log level (`RUST_LOG=warn`)
- [ ] Configure session limits
- [ ] Enable memory profiling initially
- [ ] Set up monitoring (Prometheus/Grafana)
- [ ] Configure systemd limits:

```ini
# /etc/systemd/system/zeptoclaw.service
[Service]
LimitNOFILE=65535
MemoryMax=512M
CPUQuota=80%
```

## Profiling

### CPU Profiling

```bash
# Install flamegraph
cargo install flamegraph

# Run with profiling
CARGO_PROFILE_RELEASE_DEBUG=true cargo flamegraph --bin zeptoclaw
```

### Memory Profiling

```bash
# Use dhat or heaptrack
cargo build --features dhat-heap
DHAT_HEAP_PROFILING=1 ./target/debug/zeptoclaw
```

## Scaling Strategies

### Vertical Scaling

Add more resources to single instance:
- Up to ~10,000 users on $40/month server
- Simple, no code changes

### Horizontal Scaling

For unlimited scale:

```
                    ┌─────────────┐
                    │   Load      │
                    │  Balancer   │
                    └──────┬──────┘
           ┌───────────────┼───────────────┐
           ▼               ▼               ▼
      ┌─────────┐     ┌─────────┐     ┌─────────┐
      │ZeptoClaw│     │ZeptoClaw│     │ZeptoClaw│
      │   #1    │     │   #2    │     │   #3    │
      └────┬────┘     └────┬────┘     └────┬────┘
           │               │               │
           └───────────────┼───────────────┘
                    ┌─────────────┐
                    │  Redis      │
                    │ (sessions)  │
                    └─────────────┘
```

## Further Reading

- [BENCHMARK_RESULTS.md]./BENCHMARK_RESULTS.md - Detailed benchmarks
- [SECURITY.md]./SECURITY.md - Security hardening
- [DEPLOYMENT.md]./DEPLOYMENT.md - Production deployment guide

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*Last updated: 2026-02-13*