Worker Types and Configuration

Introduction

Different worker types suit different workloads. Understanding when to use sync, async, or threaded workers optimizes performance.

Worker Types

Sync (default): One request per worker. Good for CPU-bound tasks.

Gevent: Async I/O. Good for I/O-bound tasks, many connections.

Threads: Multiple threads per worker. Balanced approach.

Configuration

python
# gunicorn.conf.py
import multiprocessing

# Sync (CPU-bound)
worker_class = 'sync'
workers = (2 * multiprocessing.cpu_count()) + 1

# Gevent (I/O-bound)
# pip install gevent
worker_class = 'gevent'
worker_connections = 1000
workers = multiprocessing.cpu_count()

# Threads (balanced)
worker_class = 'gthread'
workers = multiprocessing.cpu_count()
threads = 4

Best Practices

1. Start with sync: Simplest, adjust based on monitoring.
2. Use gevent for APIs: Better for database/API heavy apps.
3. Monitor and tune: Adjust based on actual performance.

Summary

Choose worker type based on workload: sync for CPU-bound, gevent for I/O-bound, threads for mixed. Start with (2 × CPU) + 1 workers and tune from there.