Measuring execution time

[Mark Cuss]

Hello all,

I'm not sure if this is the place to ask this particular question - if not,
my apologies ....

I am working on optimizing some software and would like to be able to
measure how long an instruction takes (down to the clock cycle of the CPU).
I recall reading somewhere about a kernel time measurement called a "Jiffy"
and figured that it would probably apply to this.

If anyone has any tips on how to figure out how to do this I'd really
appreciate it.

Thanks!

Mark