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I am a beginner and I have no clue, yet, about cloud computing nor multithreading nor multiprocessing.
I have a desktop PC with an i7 (4 cores) and I was wondering if a multi-CPUs cloud machine OR an 8+ cores machine would run ANY CODE faster than my PC without any changes in the code.
Does the machine handle the tasks distribution on the several CPUs (or the 8+ cores) by itself or is it required to adapt the code? (multithreading or multiprocessing)
For the sake of argument, let say I run a simple loop like below: 

results = {}
for i in range(10**8):
  results[i] = i**2

This takes about 67 sec on my PC (I was running something else at the same time so I'm not sure this is accurate but my timing is irrelevant anyway).
Would the exact same code be faster on a multi-CPUs machine or an 8+ cores machine compare to a single CPU 4cores machine?
If it is, in fact, required to make changes, I would appreciate any beginner links to learn about multiprocess or multithread.
Thank you for your help.

Jones
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  • The example you gave is linearly processed and has no subdivision of tasks, so it won’t be split into different processors. – Ian MacDonald Dec 31 '18 at 15:31

2 Answers2

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I'm no expert but I think it really depends on the platform that you're using to write and run your code. Some languages may support multi-threading/multi-processing natively and as such the code will run faster but others might not.

One thing is for certain you can't explicitly say that in %100 of the cases a machine with more cores/CPUs will run a given piece of code faster than a machine with lesser cores/CPUs.

Hope I helped clear things up.

Edit: This medium post regarding multiprocessing\multithreading in python looks good - Multithreading vs Multiprocessing in Python

Python multiprocessing for dummies

JBK
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A code will run faster only when it is written in parallel fashion. The snippet in the text of your question is not written parallel, so it won't run any faster.

When parallel program is being written, the programmer keeps in mind the target level of parallelization. A sequential program has parallelization level = 1. A program with N CPU-intensive threads would run most effectively on N processors (cores). A program with high parallelization level may execute slower on 2-4 core machine than sequential variant.

Alexei Kaigorodov
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