yggdrasil/DEVELOPMENT.md

Development Guide

Performance Testing

Prerequisites

Install hey (HTTP load generator) and samply (profiler):

brew install hey
cargo install samply

Benchmark

# 1. Build release binary
make build

# 2. Start server
./target/dx/yggdrasil/release/web/server

# 3. Run load test (in another terminal)
hey -c 100 -n 100000 http://localhost:8080/

Flame Graph

# 1. Build with debug symbols (required for readable flame graphs)
CARGO_PROFILE_RELEASE_DEBUG=1 make build

# Terminal 1: Start profiling
samply record -- ./target/dx/yggdrasil/release/web/server

# Terminal 2: Wait for server to start, then send load
hey -c 100 -n 100000 http://localhost:8080/

# Terminal 1: Ctrl+C after hey finishes — samply opens flame graph in browser

Key Metrics to Watch

Metric	Description
Requests/sec	Throughput
Average latency	Mean response time
P99 latency	Tail latency
Status codes	Error rate (should be 0)
Latency distribution	Consistency (tight = stable)

Flame Graph Hotspots

Expected Hotspot	Code Location	Cause
SSR rendering	Dioxus framework	Virtual DOM diff + render per request
deadpool connection acquisition	src/db/mod.rs	Connection pool contention under concurrency
moka cache lookup	src/cache.rs	Cache hit/miss overhead
tokio scheduling	tokio runtime	Async task dispatch
serde serialization	Models	Post/User serialization

Tuning

• DB_POOL_SIZE — increase if deadpool / Semaphore shows high in flame graph
• SSR_CACHE_SECS — increase to cache SSR output longer
• TOKIO_WORKER_THREADS — explicitly set worker thread count