Cloud performance vs Desktop [closed]

Question

I have developed an app to analyze videos using OpenCV and Visual Studio 2013. I was planning to run this app in the Azure assuming that it will run faster in cloud. However, to my surprise, the app ran slower than my desktop, taking about twice the time when I configured the Azure instance with 8 cores. It is a 64-bit app, compiled with appropriate compiler optimization. Can someone help me understand why am I losing time in the cloud, and is there a way to improve the timing there?

The app takes as input a video (locally in each case) and outputs a flat file with the analysis data.

I am not sure why people are voting to close this question. This is very much about programming and if possible, please help me in pinpointing the problem.

Answer 1

There is only going to be 3 reasons for this

1. Disk IO speed
2. CPU Speed
3. Memory Speed

Taking a look here you can see someone who actually checked the performance of on premise to cloud: Azure compute power: Extra Large VM slow

Basically the Ghz is most likely slower (around 1.6) and disk IO speed, while local, is normally capped at 300 or 500 IOPS, which is only just higher than 15k rpm drives and no where near SSD level.

I am not sure on memory speed. While you can keep adding cores, most programs, even ones optimized for multiple cores, have a lot of dependencies on single threads, hence slowing the whole operation down. Increased Ghz is what can make a large difference.