Server Fault is a question and answer site for system and network administrators. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

For example...when I do string.find("..."), will it be faster because the CPU is allocated more?

share|improve this question
up vote 5 down vote accepted

Very likely. And no - you should not see a difference in ONE string.find method call.

The limiting factor on most virutalization platforms is CPU and memory - you only can have that much memory and that much CPU power in one box. So, you have to keep them "aligned" by basically assuming every slice of memory comes with a slice of CPU. As such, a 2gb server will get a larger slice than a 256mb server. Totally natural.

This is normally / should be done by reservations of some part (distributing like x% of the CPU as reservations) and then giving higher allocation priorities to larger machines.

That said, unless everyone uses up his slice, the excess CPU should be available for all.

share|improve this answer
What if I have a list of 500 strings, and I am doing .find on all of them. Will I see noticible difference? – Alex Mar 15 '10 at 8:19
That totally depends. 500 strings - not likely in a visible area. I personally dont use them - I have my own server cluster for hosting - but I use virtualization heavily. It really depends how loaded their CPU's are. And how much CPU you use on a continuous level. Small spikes may not even be noticable. Running a raytrace is. – TomTom Mar 15 '10 at 8:25

Taken from the Rackspace site:

All Cloud Servers come with a certain amount of guaranteed CPU power based on the size of the servers you create. However, at times when there's extra CPU power available from the host hardware, we take advantage of it, providing your workloads extra processing power without any additional cost to you.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.