Imagination PowerVR SDK Blog

Granularity of PowerVR Series 6


#1

Hi,

In another forum the question about branching granularity of future PowerVR GPUs came up. The granularity of Series 5 appears to be one: “The branching granularity on SGX is one fragment or one vertex.” (page 22 in the “POWERVR SGX OpenGL ES 2.0 Application Development Recommendations”).

Thus, just out of curiosity: what is the branching granularity of Series 6 GPUs? 

Thanks,

Martin




#2

Hi Martin,

For our 3.0 SDK release, the performance recommendations document was updated. It now explicitly highlights differences between the Series5 and Series6 hardware.

Section 6.3. (“Flow Control”) has the following explanation:

Quote:

•  (Series 5/5XT Only) The branching granularity on PowerVR SGX hardware is one fragment
or one vertex, meaning that area of fragments don’thave to be spatially coherent in terms of
branching
•  (Series 6 Only) Unlike the previous PowerVR SGX hardware, for branching to be effective on
‘Rogue’, fragments that branch should be spatially coherent.


I hope this helps :)

Thanks,
Joe



#3
Joe wrote:
For our 3.0 SDK release, the performance recommendations document was updated. It now explicitly highlights differences between the Series5 and Series6 hardware.
...
  (Series 6 Only) Unlike the previous PowerVR SGX hardware, for branching to be effective on
‘Rogue’, fragments that branch should be spatially coherent.


Hi Joe,

thanks for mentioning the update of that document, I've missed that update.

Well, yes, that helps. Of course my next question would be: how coherent should the branching be? But I guess that depends on many factors.

Thanks,

Martin

 

#4

Hi Martin,

You’re correct that it does depend on a number of factors. Unfortunately, we cannot discuss this in any detail at this point in time.

Thanks,
Joe