[Paraview] FPS drop in stereo mode

Tue Jun 18 04:02:13 EDT 2013

Aashish,

quad stereo doesn’t work on GeForce as you already mentioned too. But
interestingly NVidia seems to support in the future (see the first post:
http://www.mtbs3d.com/phpbb/viewtopic.php?f=2&t=17077). But even with quad
stereo the problem remain.

The left and right image are merged in vtkRenderWindow::
StereoRenderComplete(void). There is an pixel-wise copying for all
stereo-types except "Crystal Eyes". Here I would request an improvement for
the future, to speed up the execution.

Thanks in advance,
Stephan

Von: Aashish Chaudhary [mailto:aashish.chaudhary at kitware.com] 
Gesendet: Dienstag, 18. Juni 2013 06:02
An: Stephan Rogge
Cc: ParaView list
Betreff: Re: [Paraview] FPS drop in stereo mode

Thanks Stephan. The conclusion makes sense as the SplitViewportHorizontal
performs operations on pixels directly. How about the quad buffer stereo?
Can you even do that on GTX card? 

- Aashish

On Mon, Jun 17, 2013 at 3:39 AM, Stephan Rogge <Stephan.Rogge at tu-cottbus.de>
wrote:
Aashish,

I've made another test on my render node [1] and my desktop PC. The FPS-drop
depends on the size of the render viewport. To showcase the drop I ran
ParaView in the "SplitViewportHorizontal" mode and play a looped animation
with an empty scene. Then I measured the FPS with three different viewport
sizes:

Resolution => FPS on render node [1]
1617 x 906 => 33 FPS (PV window maximized)
1617 x 702 => 45 FPS
1617 x 438 => 60 FPS

Resolution => FPS on desktop PC [2]
1617 x 906 => 20 FPS (PV window maximized)
1617 x 707 => 26 FPS
1617 x 292 => 60 FPS

Conclusion: The Quadro performs better within that stereo mode, but has also
a drop of ca. 50 % when the PV window is maximized.

[1] Render node:
* 2x NVidia Quadro K5000
* ParaView on git-master (latest)
* Fraps as FPS-Display
* Windows 7 64 Bit

[2] Desktop PC:
* NVidia GeForce GTX 580
* ParaView on git-master (latest)
* Fraps as FPS-Display
* Windows 7 64 Bit

Stephan

Von: Aashish Chaudhary [mailto:aashish.chaudhary at kitware.com]
Gesendet: Freitag, 14. Juni 2013 16:13
An: Stephan Rogge
Cc: ParaView list
Betreff: Re: [Paraview] FPS drop in stereo mode

On Fri, Jun 14, 2013 at 9:03 AM, Stephan Rogge <Stephan.Rogge at tu-cottbus.de>
wrote:
Aashish,

the quad buffer explenation does make sense. But after some more testing
with the "old" PV version (ParaView_4.0-RC1-51-g2965c8) on a machine with
*  a NVidia Quadro 5000 and
* a machine with 2 NVidia Quadro K5000 (SLI),
I observed a FPS drop in all stereo modes except "Crystal Eyes" which is
hard to measure with fraps. The FPS overly is not visible in that stereo
mode.

As you said earlier, the FPS will drop but not as hard as you have seen on
GTX cards. How does the FPS drop on 5000 compares with the FPS drop on GTX?

When I use "SplitViewportHorizontal" as stereo mode on my Kepler GPUs I can
see a FPS drop. Interestingly the rate depends on the ParaView's window
size. The smaller the window is the higher the rate and vice versa. I guess
that a post process, which copies pixel between buffers, need some more time
for execution. Is it possible?

Yes, that mode  performs the copy between buffers to produce the final
image. 

Regards,
Stephan

Von: Aashish Chaudhary [mailto:aashish.chaudhary at kitware.com]
Gesendet: Donnerstag, 13. Juni 2013 17:51
An: Stephan Rogge
Cc: ParaView list
Betreff: Re: [Paraview] FPS drop in stereo mode

Hi Stephan, 
GeForce GTX 580 are not great for stereo rendering as I believe they don't
support Quad buffered stereo
 (http://3dvision-blog.com/3840-nvidia-with-a-new-high-end-gpu-namely-the-ge
force-gtx-580/). 
In that case, I believe VTK will perform software stereo implementation and
that's why your performance will go down quite a bit. 

I don't have the latest card but normally the consumer level card don't
support stereo that well (although this might not be the case with recent
NVIDIA cards). 

Let us know if you find this performance degradation on your Quadro cards as
well with latest paraview. 

Thanks,

On Thu, Jun 13, 2013 at 11:13 AM, Stephan Rogge
<Stephan.Rogge at tu-cottbus.de> wrote:
Aashish,

it doesn't matter which stereo type is activated. I've got only 20 FPS...
This is tested on GeForce GTX 580. The ParaView version is pulled from
latest git-master.

Surprisingly, this problem does not occurs on my Render-PC of our
CAVE-system. There I have 2 K5000 NV Quadro cards. But the code base is
older (PV RC1), though I have to check it, with an updated code base and
see, whether this fps drop remains.

Cheers,
Stephan

Von: Aashish Chaudhary [mailto:aashish.chaudhary at kitware.com]
Gesendet: Donnerstag, 13. Juni 2013 16:49
An: Stephan Rogge
Cc: ParaView list
Betreff: Re: [Paraview] FPS drop in stereo mode

Hi Stephan, 

What particular stereo type you chose for this comparison? Also what
graphics hardware you have? 

Thanks,

On Mon, Jun 10, 2013 at 10:47 AM, Stephan Rogge
<Stephan.Rogge at tu-cottbus.de> wrote:
Hello,

I observed an unexpected frame rate drop when using one of PV's supported
stereo modes within an empty scene.

Considering
* OS: Windows
* V-Sync: On
* Application to display FPS (e.g. www.fraps.com)
* Latest ParaView from git-master

Following steps should emphasizes the frame rate drop:
1. Open ParaView without any stereo mode
2. Rotate or drag the camera in the 3D view for several seconds and watch at
the frame rate (should be around 60 FPS)
3. Close ParaView
4. Open ParaView with "--stereo" flag enabled
5. Rotate or drag the camera in the 3D view for several seconds and watch at
the frame rate (should be around 22 FPS)

Obviously, stereo rendering should take twice the time of a monocular
rendering. But this should only occurs in more complex scenes. Can anyone
reproduce this behavior? Is this a BUG?

Best regards,
Stephan

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--
| Aashish Chaudhary
| R&D Engineer        
| Kitware Inc.           
| www.kitware.com   

--
| Aashish Chaudhary
| R&D Engineer        
| Kitware Inc.           
| www.kitware.com   

--
| Aashish Chaudhary
| R&D Engineer        
| Kitware Inc.           
| www.kitware.com   

-- 
| Aashish Chaudhary 
| R&D Engineer         
| Kitware Inc.            
| www.kitware.com    