When we say that an http request takes 300ms on the server side, that number actually encompasses two phases. One phase is the time the request spends in the backlog, waiting for an available backend process (mongrel/thin/dyno). The second phase is how long it takes to process the request once it reaches the backend process. Conflating these two is a mistake, as it masks important information about what steps you can take to make your app able to handle more traffic.

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