Forums - is this the expected performance of Adreno 200?

2 posts / 0 new
Last post
is this the expected performance of Adreno 200?
Latimerius
Join Date: 4 Jul 12
Posts: 3
Posted: Thu, 2012-07-05 10:38

Hello,

in short, how many vertices roughly can Adreno 200 transform per second?

I'm increasing the number of vertices that I send to GL ES 1.1 and not surprisingly, performance (as in frame rate) degrades the more vertices I send.  However, the FPS degradation sets in way earlier than I would expect.

I have 2 Adreno 200 based Android devices here, HTC Desire (Android 2.1) and LG Optimius P500 (Android 2.2).  Optimus seems to keep up at 60 FPS just fine when I send 3000 vertices a frame (~200k vertices/sec).  At 20000 vertices/frame, FPS goes down to 40 (~800k vertices/sec).  The degradation is gradual.

The Desire shows the same, although seemingly more pronounced - e.g. sending 6000 vertices/frame results in 40 FPS (over 200k vertices/sec), 30000 vertices/frame mean 15 FPS (450k vertices/sec).

I expected performance to degrade only with million(s) vertices a second...

The vertices I'm talking about are 2D (2 floats for position each), textured (2 floats for s,t each).  No other vertex attribs are used.  They are placed in VBOs, non-interleaved (one VBO for positions, another for ST).  I tried interleaving but it had no measurable effect at all.

Note that as vertex counts are going up, most of the additional vertices in these measurements belong to degenerated triangles (all triagle vertices at (0.0f,0.0f), all st coords zero as well) so they should not put any pressure on stages past culling.

It tried to use the Adreno Profiler to investigate but the tool is unfortunately way too picky to be useful to me (only works with some OSs, some graphics cards, some phones...).  About the only interesting datum I was able to get was that on the Optimus (the profiler won't work with Desire), low vertex counts had the Vertex Fetch Stall percentage close to zero, for higher numbers of vertices per frame the Vertex Fetch Stall oscilated between 10-15%, up to 20% sometimes.  Does that indicate a problem of some kind?

Especially with the Desire, I expected these devices to be fill bound, not transform bound - am I misinterpreting something?

Cheers!

 

  • Up0
  • Down0
Latimerius
Join Date: 4 Jul 12
Posts: 3
Posted: Fri, 2012-07-13 02:18

Hello?

No Qualcomm people able or willing to discuss the performance of your own chips - after more than a week?

I understand I'm not entitled to any support, however you should understand that you either need to publish good documentation for your GPUs so that we can figure out problems ourselves, or talk to developers with specific problems (obviously preferably both).  Not doing either and leaving people out in the cold will not give you good developer relations.

Thanks.

 

  • Up0
  • Down0
or Register

Opinions expressed in the content posted here are the personal opinions of the original authors, and do not necessarily reflect those of Qualcomm Incorporated or its subsidiaries (“Qualcomm”). The content is provided for informational purposes only and is not meant to be an endorsement or representation by Qualcomm or any other party. This site may also provide links or references to non-Qualcomm sites and resources. Qualcomm makes no representations, warranties, or other commitments whatsoever about any non-Qualcomm sites or third-party resources that may be referenced, accessible from, or linked to this site.