21

As most people agree, encouraging developers to make fast code by giving them slow machines is not a good idea. But there's a point in that question. My dev machine is fast, and so I occasionally write code that's disturbingly inefficient, but that only becomes apparent when running it on other people's machines.

What are some good ways to temporarily slow down a turbocharged dev machine? The notion of "speed" includes several factors, for example:

  • CPU clock frequency.
  • Amount of CPU cores.
  • Amount of memory and processor cache.
  • Speed of various buses.
  • Disk I/O.
  • GPU.
  • etc.
Community
  • 1
Joonas Pulakka
  • 23,562

5 Answers5

39

Run your tests in a virtual machine with limited memory and only one core.

The old machines people still may have now are mostly Pentium 4 era things. That's not that unrealistic - I'm using one myself right now. Single core performance on many current PCs normally isn't that much better, and can be worse. RAM performance is more important than CPU performance for many things anyway, and by limiting a little more harshly than for an old 1GB P4, you compensate for that a bit.

Failing that, if you're willing to spend a bit, buy a netbook. Run the tests on that.

11

The way to spot significant algorithm inefficiency is to profile you code. The way to catch memory overuse is to first understand how much memory your target uses have, and then design accordingly, and regularly test in that environment.

If you are writing threaded code, testing on multiple machines with differing CPU speeds will help highlight specific timing related bugs in your thread handling, but aggressive unit testing of thread logic is a must.

Michael Shaw
  • 10,114
10

Anything that you do to slow down your machine would probably be a hack.

Here are a couple of suggestions:

  • Use virtual machines
  • Profile the code on your machine, looking for bottlenecks
  • Use an old machine for "performance testing"
Jason
  • 541
9

Install Virtual PC, create a hardware profile, create a virtual machine and start playing :)

devnull
  • 3,055
4

Realise this is quite an old question, but for anyone else in this situation; you could try CPUKiller. It basically is a small app that you can configure to consume different %'s of your processor. http://www.cpukiller.com/

Dave
  • 41