[Mesa-dev] [PATCH] Integrate precise trig into configuration infrastructure

[Eero Tamminen]

Hi,

On 12.05.2016 11:05, Kenneth Graunke wrote:
> On Thursday, May 12, 2016 11:15:58 AM PDT Eero Tamminen wrote:
>> The known cases where this workaround caused slowdown were fixed,  so
>> why not just unconditionally enable it?
>>
>> Or is there still some case where workaround causes a measurable slowdown?
>
> I mean, it still makes sin/cos instructions twice as slow unless the
> sin/cos happens to be multiplied by a constant.  So that's still fairly
> unfortunate.

Multiply is faster instruction than sin/cos, and depending on what else 
the shader does, good scheduler may be able to hide latency of 
additional multiply, so I don't think it's quite that bad. :-)


> Though, if there's really nothing hurt by this, then it might be
> reasonable.


	- Eero