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Re: Measurement of CPU usage
de Al Klein 05/07/2006 03:02
On 6 May 2006 10:50:26 -0700, "PaulFXH" <paul_hackett2@yahoo.com.br>
wrote:
>However, I'm NOT looking for a means to see what my CPU usage is--I
>already have about 6 utilities showing me this.
>What I want is an explanation as to why these utilities provide such
>startlingly different results.
>Which one is right?
>Or, are they both right with different interpretations?
CPU usage is always 100% - the CPU doesn't (usually) stop. The
question is which program is using what percentage of the CPU's time.
If you're looking at a program that claims to show actual CPU usage,
unless it's claiming 100% it's wrong.
If you're looking at a program that claims to show the percentage of
CPU time used by each program, be aware that usage is dynamic - it
varies microsecond by microsecond. While the system idle process (the
loop in the OS that waits for something to happen) usually gets most
of the CPU time, it gives its time up whenever another program needs a
slice. Unless both programs are reporting the same thing at the same
time (and that's impossible, due to the nature of digital computers),
they're going to give you different results. A single program will
give you different results moment by moment.