Why server-side is slow?

I know 2 ways of answering this question.

One steals time with no results, while another one leads to correct answer.

First: Random guess

  • Slow as caches are too small, we need to increase them
  • Slow as server isn't powerful enough, we need to get a bigger box

Characteristics:

  • Based on past experience (cannot guess something never faced before)
  • Advantage: Does not require any investigation effort
  • Disadvantage: As accurate as shooting in the forest without aiming

Second: Profile code execution flow

The dynamic profiling is like a video of 200 meter sprint showing:

  • How fast each runner is
  • How much time does it take for each runner to finish
  • Are there any obstacles on the way?

Collecting dynamic code profile

PerfView is capable of collecting the data in 2 clicks, so all you need to do is:

  • Download the latest PerfView release, updated quite often
  • Run as admin
  • Click collect & check all the flags
  • Stop in 20 sec

Downloading PerfView

Even though I hope my readers are capable of downloading files from link without help, I would drop an image just in case:

Ensure to download both PerfView and PerfView64 so any bitness could be profiled.

Running the collection

  • Launch PerfView64 as admin user on the server
  • Top menu: Collect -> Collect
  • Check all the flags (Zip & Merge & Thread Time)
  • Click Start collection
  • Click Stop collection in ~20 seconds
How to collect PerfView profiles

Collect 3-4 profiles to cover different application times.

The outcome is flame graph showing the time distribution:

Summary

The only way to figure out how the wall clock time is distributed is to analyze the video showing the operation flow. Everything else is a veiled guessing-game.

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