Some scenes render transparent with big tiles and OpenCL rendering #49124

New Issue

mathieu menuet · 2016-08-20T11:13:56+02:00

mathieu menuet commented

2016-08-20 11:13:56 +02:00

System Information
Linux with GPU Pro 16.3 and Windows with 16.8.1 on RX480

Blender Version
Broken: cf53389

Short description of error
Some scene (most of the time big ones) will render only transparent if tiles are set too big. Problem is that AMD cards don't like small tiles and it let the user fiddle with tile size or worse, start a video render and only get full transparent images.

Exact steps for others to reproduce the error

Render the victor scene from the cycles benchmark pack (https://download.blender.org/demo/test/cycles_benchmark_20160228.zip) with latest AMD drivers. Set the tile to 384384 or 512512: it renders correctly.
Set the tile so that it fills the whole image: it renders transparent.

**System Information** Linux with GPU Pro 16.3 and Windows with 16.8.1 on RX480 **Blender Version** Broken: cf53389 **Short description of error** Some scene (most of the time big ones) will render only transparent if tiles are set too big. Problem is that AMD cards don't like small tiles and it let the user fiddle with tile size or worse, start a video render and only get full transparent images. **Exact steps for others to reproduce the error** 1) Render the victor scene from the cycles benchmark pack (https://download.blender.org/demo/test/cycles_benchmark_20160228.zip) with latest AMD drivers. Set the tile to 384*384 or 512*512: it renders correctly. 2) Set the tile so that it fills the whole image: it renders transparent.

mathieu menuet commented

2016-08-20 11:13:56 +02:00

Changed status to: 'Open'

mathieu menuet commented

2016-08-20 11:13:56 +02:00

Added subscriber: @bliblubli

Brecht Van Lommel commented

2016-08-20 11:48:47 +02:00

Added subscriber: @brecht

Brecht Van Lommel commented

2016-08-20 11:48:47 +02:00

Are there any error messages, or something printed with --debug-cycles?

Are there any error messages, or something printed with `--debug-cycles`?

mathieu menuet commented

2016-08-20 14:31:39 +02:00

first test made a system lock. Only mouse was moving. Had to hard reboot. Will try again.

mathieu menuet commented

2016-08-20 15:01:56 +02:00

On the original scene giving the problem, it works without hard locking. But no error in log. Only 2 lines more to give render times (from about ~3600 lines of logging). Comparing a good render log and a bad render log quickly, I see no difference. No error, no fail, same line numbers in log...
Only image is black, transparent or computer locks when tile size is above a certain limit.

Common point between those files failing to render at higher tile size is that they are already pretty heavy. So it seems some allocation is not working well. But the last lines in log are about device_opencl.cpp allocating for textures and co. and there is no error. So not sure what happens.

I guess you could reproduce the error on cards with less memory by adding a highly subdivided mesh with some hires HDRs to fill the memory.

From memory, in 2.76b with R9 280X, if a scene was not fitting, it would nicely give an error message like "OpenCL device out of memory".

On the original scene giving the problem, it works without hard locking. But no error in log. Only 2 lines more to give render times (from about ~3600 lines of logging). Comparing a good render log and a bad render log quickly, I see no difference. No error, no fail, same line numbers in log... Only image is black, transparent or computer locks when tile size is above a certain limit. Common point between those files failing to render at higher tile size is that they are already pretty heavy. So it seems some allocation is not working well. But the last lines in log are about device_opencl.cpp allocating for textures and co. and there is no error. So not sure what happens. I guess you could reproduce the error on cards with less memory by adding a highly subdivided mesh with some hires HDRs to fill the memory. From memory, in 2.76b with R9 280X, if a scene was not fitting, it would nicely give an error message like "OpenCL device out of memory".

Sergey Sharybin commented

2016-08-23 12:43:48 +02:00

Added subscriber: @Sergey