Time Sensitive Functionality in Elixir

Questions & Help Questions
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1

I need to understand more clearly how the runtime & scheduler works in regards to time sensitive functionality.

  1. I would like to measure the response time of an HTTP Request to an external server. I want this measurement to be the exact time it took for the external server to respond. I can record the time it takes for the function to finish, but if the CPU is busy, etc this might not be the true response time. What is the best way to do this and why?

  2. I want to run repeat cron-like tasks on a timer. How confident can I be that the task will run at the exact given time? If I overload it - say by scheduling 10,000 tasks at the same time - what will happen? Will they be scheduled in order? And can I retrieve the actual execution time?

In general I am still trying to understand when Asynchronous code should be a Process / Stream / GenServer / Task / Agent, and any guidance / resources here would be great!

This is a Phoenix project.

Thanks!