The author delves into the common belief that Rails applications are IO-bound due to database issues. They argue that while some applications may indeed be IO-bound, many performance issues stem from database optimization. They highlight the impact of YJIT on reducing application latency, challenging the notion of IO-heavy Rails apps. The content emphasizes the importance of understanding the IO to CPU ratio in Rails apps for deployment decisions. The piece emphasizes balancing developer happiness with performance considerations in Ruby code. Additionally, it delves into the complexities of CPU starvation vs. IO wait times, shedding light on common misconceptions in app performance analysis.
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https://byroot.github.io/ruby/performance/2025/01/23/the-mythical-io-bound-rails-app.html