[ltp] Running without a battery?

[Behdad Esfahbod]

On Wed, 14 Jan 2004, mukesh agrawal wrote:

> On Wed, 14 Jan 2004, Dr. Jason Breitweg wrote:
>
> > Yeah, that would be really cool if you could check that out.  How does
> > one tell if the CPU is running at a lower speed?
>
> Any program that just executes a CPU loop would work. bogomips is one such
> program, that might already be installed.
>
> If not, something like the following should do the trick:
>
> --- spin.c ---
>
> main() {
> 	int i = 1E6;
>
> 	while (i) --i;
> }
>
> --------------
>
> % gcc spin.c -o spin
> % time spin

> Just compare how long it takes to execute (plugged in vs unplugged, or
> whatever scenarios you want).
>
> You might need to adjust the value of i up or down, depending on how long
> it takes to execute. (If it returns in less than 1 second in both cases,
> make i bigger.)

Not a single loop works still ;).  On my P4 2.4, 1E9 takes 0.7s
and 1E10 apparently overflows 32bit int.

behdad