World multiple importance sample CUDA error #40228

System Information
Win 7 64 bits, AMD Phenom II X6 1090T
8Go
GPU GEFORCE 580 3Go, TITAN, TITAN BLACK

Blender Version
Any version since Multiple Importance Sampling have existed in the world menu (!)

Short description of error
Enabling World menu Multiple Importance Sampling with all GPU enabled (even the one to display) cause "CUDA error: Unknown error in cuCtxSynchronize()" (and crashe renders)
Turn Off World menu Multiple Importance Sampling and render works fine !

Best regards

Changed status to: 'Open'

Added subscriber: @remibug

Does it work with the individual GPUs?

Yes works fine with only one GPU (even the displaying one).

Added subscriber: @zuggamasta

System Information
Win 7 64 bits, Intel Core i7 X980 3.33Ghz, 24GB ram
3 GPU setup:
2x GEFORCE 480, GEFORCE 750ti

Blender Version
Multiple versions with sm_50 compatibility.

Error
When using all 3 GPUs, the Mem Load gets unusual big with the error:
"CUDA error: Unkown CUDA error value in cuMemFree(cida_device_ptr(mem.device_pointer))"
BVH etc. gets built but then the image stays black

When deactivating MIS, everything works as expected.

Added subscriber: @ThomasDinges

Please give the specific version number of the latest version that crashes, it's not clear to me if this happens in the 2.70a release or the latest test builds as well.

Does this happen on the default cube .blend file, no settings changed except enabling this option? Does the Map Resolution have an influence, does lowering it stop the error?

Hi Brecht,

The build from today 07e8096 win64, still crashes with the default cube + activated MIS

When Lowering the Map Resolution from the default 256 down to 128 the default cube is rendered with no CUDA error.
A Map Resolution of 255 is the highest value which worked for me. Everything higher crashes.

Hi guys,
Win 7 64 bits, AMD Phenom II X6 1090T
Hash 19e627c (official 2.70, I presume) and buildbot build : Hash 30361a7

Factory Setting with default cube, 3 GPU rendering, Multi Importance Sampling Enabled --> Crash.

Map Resolution [0;255] = works fine
Map Resolution > 255 = crash.

I think a damn real bug has been spotted !

Thanks.

This issue was referenced by 865dfa8a7e

Changed status from 'Open' to: 'Resolved'

Closed by commit 865dfa8a7e.

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World multiple importance sample CUDA error #40228