Rendering volume scatter with GPU OpenCL comes to an halt after a few seconds #50985

New Issue

bigbad · 2017-03-17T18:45:13+01:00

bigbad commented

2017-03-17 18:45:13 +01:00

System Information
Operating system: Win 10 64-bit Home Edition
Graphics card: AMD ASUS R9 390X 8GB, latest drivers

Blender Version
Broken: 2.78 9d873fc

Short description of error
Rendering volume scatter with GPU OpenCL comes to an halt after a few tiles. It just stops to render but the GPU Usage hovers about 50%-60% when it stops to render.

Exact steps for others to reproduce the error

Use the BMW27.blend file from benchmark. Add a large cube that engulfs the whole scene and add a volume scatter shader in Volume. Use OpenCL GPU. Press F12. Blend updated for testing.

BMW27 bug light scatter.blend

**System Information** Operating system: Win 10 64-bit Home Edition Graphics card: AMD ASUS R9 390X 8GB, latest drivers **Blender Version** Broken: 2.78 9d873fc **Short description of error** Rendering volume scatter with GPU OpenCL comes to an halt after a few tiles. It just stops to render but the GPU Usage hovers about 50%-60% when it stops to render. ![bug_lightscatter.png](https://archive.blender.org/developer/F512322/bug_lightscatter.png) **Exact steps for others to reproduce the error** Use the BMW27.blend file from benchmark. Add a large cube that engulfs the whole scene and add a volume scatter shader in Volume. Use OpenCL GPU. Press F12. Blend updated for testing. [BMW27 bug light scatter.blend](https://archive.blender.org/developer/F512325/BMW27_bug_light_scatter.blend)

bigbad commented

2017-03-17 18:45:13 +01:00

Changed status to: 'Open'

bigbad commented

2017-03-17 18:45:13 +01:00

Added subscriber: @bigbad

soulfire commented

2017-03-19 08:34:59 +01:00

Added subscriber: @TomG

Hristo Gueorguiev commented

2017-03-24 21:31:47 +01:00

Added subscriber: @nirved-1

Hristo Gueorguiev commented

2017-03-24 21:31:47 +01:00

Cause is unsafe compiler options. Changing it to a safe one does performance penalty 1%.
P457: Fix for #50985

diff --git a/intern/cycles/device/opencl/opencl_base.cpp b/intern/cycles/device/opencl/opencl_base.cpp
index 0328dfe..c3a499d 100644
--- a/intern/cycles/device/opencl/opencl_base.cpp
+++ b/intern/cycles/device/opencl/opencl_base.cpp
@@ -612,7 +612,7 @@ void OpenCLDeviceBase::shader(DeviceTask& task)
 
 string OpenCLDeviceBase::kernel_build_options(const string *debug_src)
 {
-	string build_options = "-cl-fast-relaxed-math ";
+	string build_options = "-cl-no-signed-zeros -cl-mad-enable ";
 
 	if(platform_name == "NVIDIA CUDA") {
 		build_options += "-D__KERNEL_OPENCL_NVIDIA__ "

Cause is unsafe compiler options. Changing it to a safe one does performance penalty 1%. [P457: Fix for #50985](https://archive.blender.org/developer/P457.txt) ``` diff --git a/intern/cycles/device/opencl/opencl_base.cpp b/intern/cycles/device/opencl/opencl_base.cpp index 0328dfe..c3a499d 100644 --- a/intern/cycles/device/opencl/opencl_base.cpp +++ b/intern/cycles/device/opencl/opencl_base.cpp @@ -612,7 +612,7 @@ void OpenCLDeviceBase::shader(DeviceTask& task) string OpenCLDeviceBase::kernel_build_options(const string *debug_src) { - string build_options = "-cl-fast-relaxed-math "; + string build_options = "-cl-no-signed-zeros -cl-mad-enable "; if(platform_name == "NVIDIA CUDA") { build_options += "-D__KERNEL_OPENCL_NVIDIA__ " ```

bigbad commented

2017-03-25 01:12:41 +01:00

Thanks Hristo for looking into that and giving an answer and a solution. Is there a way to enable safe compiler options from the terminal or within blender? Or is it hardcoded?

Hristo Gueorguiev was assigned by Aaron Carlisle

2017-04-11 01:05:41 +02:00

blender-admin commented

2017-04-25 20:10:51 +02:00

This issue was referenced by blender/cycles@32af06f8ba

This issue was referenced by blender/cycles@32af06f8ba756b0e5e40b1fcd7a57bb18fe69cc8

blender-admin commented

2017-04-25 20:10:51 +02:00

This issue was referenced by e91dc3a97c

This issue was referenced by e91dc3a97c0ce1951ce76790210f7197ab9e014a

Hristo Gueorguiev commented

2017-04-25 20:26:07 +02:00

Changed status from 'Open' to: 'Resolved'

Hristo Gueorguiev closed this issue

2017-04-25 20:26:07 +02:00

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Rendering volume scatter with GPU OpenCL comes to an halt after a few seconds #50985