## GPU-Rendering: Rectangular stripes & Top to Bottom

Discussions related to GPU Acceleration in LuxRender

### GPU-Rendering: Rectangular stripes & Top to Bottom

The background of this idea is, that In Win 10, i have a Open CL_Memory error if i use TIle-Sizes > 64.
While i found out, that on my System larger tiles bring higher GPU Rendering speed.

Actually i tested with Windows 10 and Blender Cycles, but theoretically it should be similar with Luxblender.

Since the Windows 10 Upgrade the OpernCL Rendering is more or less broken.
Wether on Cycles and on Luxrender also. I have the newest AMD Driver 16.1, i installed the newest Luxrender.
But it will only render small scenes in small "Tiles".

This video shows it.
viewtopic.php?f=17&t=12667

So in Blender, newest development version, it is now possible to set "Stripe sizes" of the GPU-Render-TIles.

As in Graphics cards, Memory access and cache is very important for speed, i thought "Instead of using a quadratic Tile (=4096 Pixels per Tile)
I use a 240x8 Long rectangular Tile (in cycles).

As Graphics memory is organize "Linear", the caching should have an advantage about it.
Also my impression was that it runs faster. Its just rendering so i can not test it ...

Therefore maybe someone else can also test it on their GPU. Instead of quadratic Tiles, try rectangular Tiles, that are long in X-direction.
Use the same number of Pixels per "Tile". Just make the long in the X-direction and shorter in Y (currently i use 240x8).

Render the same picture twice, fist with the current standart settings and quadratic tiles, then with a "Top to Bottom" setting and rectangular tiles.

Which is faster?

PS: I think it will only make an difference in GPU Renderin, not in CPU Rendering.
Theogott

Posts: 142
Joined: Mon Nov 30, 2015 3:59 pm

### Re: GPU-Rendering: Rectangular stripes & Top to Bottom

If you want to test this with LuxCore through LuxBlend, you can put this into the "custom properties" field:
Code: Select all
tile.size.x = 100|tile.size.y = 50

The chosen values are of course examples. This should work in Classic and LuxCore API mode.

B.Y.O.B.

Posts: 5180
Joined: Wed Nov 10, 2010 4:10 pm
Location: Germany

### Re: GPU-Rendering: Rectangular stripes & Top to Bottom

Good to know, i will try that and tell you the results. When my actual rendering is ended.
Theogott

Posts: 142
Joined: Mon Nov 30, 2015 3:59 pm

### Re: GPU-Rendering: Rectangular stripes & Top to Bottom

Hi, checking tile setting give some funny results.
Render is significant slower with tile.size.x = 160|tile.size.y = 20, for example.

Cheers, mib
Opensuse Leap 42.1/64 i5-3570K 16 GB
GTX 760 4 GB GTX 670 2 GB 361.42 Blender 2.7 Octane 3.0
mib2berlin

Posts: 182
Joined: Mon Jun 22, 2009 3:18 pm

### Re: GPU-Rendering: Rectangular stripes & Top to Bottom

mib2berlin wrote:Hi, checking tile setting give some funny results.

In case you mean the tile highlighting (red/green/yellow outlines), that's probably just a LuxBlend bug (I never tested that code with asymmetric tiles before). The rendering will still run correctly.

B.Y.O.B.

Posts: 5180
Joined: Wed Nov 10, 2010 4:10 pm
Location: Germany

### Re: GPU-Rendering: Rectangular stripes & Top to Bottom

Yes, rendering work as expected.

CHeers, mib
Opensuse Leap 42.1/64 i5-3570K 16 GB
GTX 760 4 GB GTX 670 2 GB 361.42 Blender 2.7 Octane 3.0
mib2berlin

Posts: 182
Joined: Mon Jun 22, 2009 3:18 pm