Influence of frequency

Thread Starter

ga.eseco

Joined Jul 28, 2009
1
Hi,

I'm trying to understand how the frequency of a processor has an influence on how quickly a task will be completed.

I've done some tests on a PXA270 for the company i'm working for and it appears that if I use a frequency, which is twice another, then the time required to complete a task is divided by two.

I'm a little surprised with that result, it seems 'too simple', so I'm trying to figure out how I could explain it.

For the test I just made the processor compelte a loop, also i'm not sure it's the best way to test the processor.

Any idea on how I could explain this result, or maybe what kind of test I could run to go further.

Thanks,
 
Last edited by a moderator:

russ_hensel

Joined Jan 11, 2009
825
Unless you use delay routines or synchronize to outside events, I have a uc based clock that gives the right time despite which processor speed I pick ( time comes from the power line )
 

mik3

Joined Feb 4, 2008
4,843
A processor simply transfers data between registers and does what it does. If you have a bucket and transfer water between two tanks, say one bucket every minute, what will happen if you transfer one bucket every half a minute?
The tank will empty/fill twice as fast as before. It is the same idea except that a processor transfers data.
 

rjenkins

Joined Nov 6, 2005
1,013
It is that simple UNTIL you get to real-world interractions...

If your program has to wait for anything external, whether it be a serial port, LCD or writing to flash memory, your actual gains will be rather less than the 'pure software' speed increase.
 
Top