[IPOL discuss] Ask about server

[Miguel Colom]

Quoting Khánh V? <vudinhkhanh1995 at gmail.com>:

> I want say question about server:
> When I test online to compare 2 imgage using SURF on
> http://demo.ipol.im/demo/69/ I waste about 10s. But when I download code
> and run it in my computer It run 150s. My computer CPU core i3. I don't
> understand.

Dear Khánh V,

One technique used in many programs to speed up is symmetric  
multiprocessing [1], where many units of the CPU (called "cores")  
execute different parts of the program at the same time.

Let's assume that your Core i3 CPU has 4 cores (or technically, 2 real  
cores which at the end it's 4 hyperthreaded cores) running at 1.20 GHz.

The IPOL server running that demo has 32 cores running at 2.27 GHz.

Thus, a very rough estimate gives that an execution of 10 seconds in  
the IPOL server would take (approximately) 10 * (32 / 4) * (2.27/1.20)  
= 151 seconds in that hypothetical i3 CPU.

In short, the more cores a system has, the faster it'll go. Assuming  
that it can be well parallelized, of course.

Best,
Miguel

[1] https://en.wikipedia.org/wiki/Symmetric_multiprocessing