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rust.cpu_in_async

Performance High

Detects CPU-intensive operations in async functions that block the tokio runtime.

Why It Matters

CPU work in async:

Blocks runtime threads — All other tasks stall
Destroys concurrency — Async benefits lost
Causes timeouts — Other operations delayed

Example

// ❌ Before (blocking async runtime)
async fn process() {
    let result = expensive_computation(); // Blocks runtime!
}

// ✅ After (offload to blocking thread)
async fn process() {
    let result = tokio::task::spawn_blocking(|| {
        expensive_computation()
    }).await?;
}

What Unfault Detects

Heavy computations in async fns
Loops without yield points in async
Cryptographic operations in async