[Pixman] Performance of radial gradients
Luca Barbato
lu_zero at gentoo.org
Mon Feb 22 09:40:34 PST 2010
On 02/22/2010 05:42 PM, Jonathan Morton wrote:
> On Mon, 2010-02-22 at 18:39 +0200, Siarhei Siamashka wrote:
>
>> The usage of sqrt is probably not a fatal performance problem.
>
> Most desktop-style PowerPCs in the wild have a dedicated fsqrt{f}
> instruction (with approximately the same expense as fdiv{f}), and
> Altivec can efficiently use the Newton-Raphson method as well.
>
> Even x87 has transcendentals covered rather well. In fact it's one of
> the few things it's genuinely good at, justifying the relatively high
> expense of an FPU in the early days.
>
> So provided there aren't too many of them, I would not consider sqrt a
> huge problem - just like a divide really.
Right, it isn't something fatal, still if we could do w/out could be nicer.
lu
--
Luca Barbato
Gentoo/linux
http://dev.gentoo.org/~lu_zero
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