How much is 1/8th of a core?

Question

I'm new to cloud computing and, for the life of me, I can't figure out how "much" 1/8th of a core is in practical terms.

I know what kind of CPUs Amazon EC2 are using for m1.small, but let's say (for education purposes) that it is a single-core 1GHz CPU.

How is 1/8th of core calculated? Does it mean my application will run at 128MB RAM and 1/1GHz of CPU? Or will my application be able to run only a certain number of operations/CPU cycles before I'll be charged for an addition app-cell?

What I need is a practical explanation of the phrase. Perhaps, on an a simple vert.x HTTP server, where each successful connection calculates 2 + 3? Vert.x uses less than 128MB of RAM.

Answer 1

Afaik, you don't have a limit on the number of cycles: if you application requires many CPU cycles it will probably run slower since it would only use 1/8 of core.

Regarding the memory, if you are just using 1 app cell but your app requires more than 128MB, then it will probably result in an OUT OF MEMORY exception.

Answer 2

slicing of the server to 8th isn't as mathematic as you expect. Sharing server resource with multiple tenant allows to better use CPU globaly, compared to a classic server, so even you path inly 1/8 of the server you actually get more resources, but only when you application actually use them.