Re: sched_clock() uses are broken

Andi Kleen
2006-05-02T17:01:23Z

On Tuesday 02 May 2006 18:50, Russell King wrote:

> You're right assuming you have a 64-bit TSC, but ARM has at best a
> 32-bit cycle counter which rolls over about every 179 seconds - with
> gives a range of values from sched_clock from 0 to 178956970625 or
> 0x29AAAAAA81.
>
> That's rather more of a problem than having it happen every 208 days.

Ok but you know it's always 32bit right? You can fix it up then
with your proposal of a sched_diff()

The problem would be fixing it up with a unknown number of bits.

-Andi