[Interest] debug scenegraph batching performance

[Gunnar Sletta]

Hi,

Since you have 12 elements in the grid and batches with 12 nodes in each, that looks "right". 

I know that debugging the batching is a bit cumbersome and I started looking at a crude visualizer (https://codereview.qt-project.org/#change,73469) which helps a little bit with identifying what fits where.

cheers,
Gunnar


On 06 Jan 2014, at 07:17, Narayanarao Rao <nari01 at gmail.com> wrote:

> I have a grid view that I want to optimize. I found that most of the cpu time is taken in rendering the gridview. I need to make sure scenegraph batches as many operations as possible. To do this, I set all the env variables suggested in docs like QSG_RENDERER_DEBUG=render, QSG_RENDERER_DEBUG=dump etc.
> 
> However these give information only in terms of nodes. It is difficult for me to associate these nodes to actual qml elements. How can I see which qml elements are getting batched and which are not? I can guess which nodes are which qml elements but I think there should be a simpler way to get direct mapping. Here is the debug output with my gridview:
> 
> There are 12 elements visible on the gridview, as you can make out from the below logs:
> 
> Renderer::render() QSGRenderer(0xa2c378) "rebuild: none" 
> Rendering:
>  -> Opaque: 12 nodes in 2 batches...
>  -> Alpha: 51 nodes in 14 batches...
>  - 0xa051f0 [retained] [noclip] [opaque] [  merged]  Nodes:   11  Vertices:    44  Indices:    66  root: 0x555870 
>  - 0x9e0d50 [  upload] [noclip] [opaque] [  merged]  Nodes:    1  Vertices:     4  Indices:     6  root: 0x555870 
>  - 0x561018 [retained] [noclip] [ alpha] [  merged]  Nodes:    1  Vertices:     4  Indices:     6  root: 0x0 
>  - 0x560fe0 [retained] [noclip] [ alpha] [  merged]  Nodes:    1  Vertices:    12  Indices:    18  root: 0x0 
>  - 0x9893a8 [retained] [noclip] [ alpha] [  merged]  Nodes:    4  Vertices:   104  Indices:   156  root: 0x0 
>  - 0x9d4b40 [retained] [noclip] [ alpha] [  merged]  Nodes:   12  Vertices:    48  Indices:    72  root: 0x555870 
>  - 0x5c3128 [retained] [noclip] [ alpha] [  merged]  Nodes:   12  Vertices:    48  Indices:    72  root: 0x555870 
>  - 0x989bb8 [retained] [noclip] [ alpha] [  merged]  Nodes:   12  Vertices:   672  Indices:  1008  root: 0x555870 
>  - 0x9d63f0 [retained] [noclip] [ alpha] [  merged]  Nodes:    1  Vertices:     4  Indices:     6  root: 0x0 
>  - 0xa178f8 [retained] [noclip] [ alpha] [  merged]  Nodes:    1  Vertices:   148  Indices:   222  root: 0x0 
>  - 0xa18030 [retained] [noclip] [ alpha] [  merged]  Nodes:    1  Vertices:    80  Indices:   120  root: 0x0 
>  - 0x67c170 [retained] [noclip] [ alpha] [  merged]  Nodes:    1  Vertices:   268  Indices:   402  root: 0x0 
>  - 0x9dda48 [retained] [noclip] [ alpha] [  merged]  Nodes:    1  Vertices:   144  Indices:   224  root: 0x0 
>  - 0x5d3e48 [retained] [noclip] [ alpha] [  merged]  Nodes:    1  Vertices:     8  Indices:    12  root: 0x0 
>  - 0x5d3e80 [retained] [noclip] [ alpha] [  merged]  Nodes:    2  Vertices:    48  Indices:    72  root: 0x0 
>  - 0x687f48 [retained] [noclip] [ alpha] [  merged]  Nodes:    1  Vertices:     4  Indices:     6  root: 0x0 
> 
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