Re: [patch v5 06/15] sched: log the cpu utilization at rq

[Peter Zijlstra]

On Wed, 2013-02-20 at 22:33 +0800, Alex Shi wrote:
> > There's generally a better value than 100 when using computers..
> seeing
> > how 100 is 64+32+4.
> 
> I didn't find a good example for this. and no idea of your suggestion,
> would you like to explain a bit more?

Basically what you're doing ends up being fixed point math, using 100 as
unit is inefficient, pick a power-of-2 and everything reduces to
bit-shifts.

http://en.wikipedia.org/wiki/Fixed-point_arithmetic

So use 128 or 1024 or whatever and you don't need mult and div
instructions to represent [0,1]

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/