Puma server configuration in Ruby on Rails - Performance & Optimization

Performance: Puma server configuration

HIGH IMPACT

This affects how fast the Rails app can handle incoming web requests and how well it uses server resources.

Configuring Puma to handle concurrent web requests efficiently

Ruby on Rails

threads 5,16
workers 2

Allows multiple threads per worker and multiple workers, enabling parallel request processing.

📈 Performance GainImproves throughput and reduces request wait time under load

Configuring Puma to handle concurrent web requests efficiently

Ruby on Rails

threads 1,1
workers 1

Using only one thread and one worker limits concurrency, causing slow response under multiple requests.

📉 Performance CostBlocks requests sequentially, increasing response time and reducing throughput

Performance Comparison

Pattern	Concurrency	Memory Usage	Startup Time	Verdict
threads 1,1 workers 1	Single request at a time	Higher per worker	Slower	[X] Bad
threads 5,16 workers 2	Multiple requests concurrently	Optimized with preload	Faster	[OK] Good

Rendering Pipeline

Puma handles incoming HTTP requests by distributing them across threads and workers, which process the requests and send responses. Efficient configuration reduces queuing delays and CPU contention.

→Request Queuing

→Thread Scheduling

→Process Forking

⚠️ BottleneckInsufficient threads or workers causing request queuing delays

Core Web Vital Affected

INP

This affects how fast the Rails app can handle incoming web requests and how well it uses server resources.

Optimization Tips

1Set Puma threads to match expected concurrency for your app workload.

2Use multiple workers to utilize multiple CPU cores effectively.

3Enable preload_app! to reduce memory usage and speed up worker boot.

Performance Quiz - 3 Questions

What is the main benefit of increasing Puma worker count?

A Improves CSS rendering speed

B Allows handling more requests in parallel by using multiple processes

C Reduces memory usage by sharing threads

D Decreases database query time

DevTools: Performance (Rails logs and server monitoring)

How to check: Monitor request queue time and response time under load using Rails logs and tools like puma-status or New Relic.

What to look for: Low request queue time and consistent response times indicate good Puma configuration.