luxrays - segfault

[PPatrick]

Hi,

I got a segmentation fault every time that one of the luxrays samples (slg2, benchsimple, ... ) execute the opencl "program.build(params)" in the openclidevice.cpp only with the GPU. (And for every BVH)

Anyone get the same problem and solve it ?

Linux Mint 12 Lisa (64 bits)
GPU : ATI RADHEON 4650

Thanks.

[Dade]

I got a segmentation fault every time that one of the luxrays samples (slg2, benchsimple, ... ) execute the opencl "program.build(params)" in the openclidevice.cpp only with the GPU. (And for every BVH)

Anyone get the same problem and solve it ?

Linux Mint 12 Lisa (64 bits)
GPU : ATI RADHEON 4650

HD4650 is a bit old and AMD OpenCL drivers have always been in beta for the HD4xxx family however do you have installed the latest Catalyst drivers ?

And what is the output of the clinfo command ?

Have you tried to run only with the OpenCL CPU device (it must work no matter the GPU you have) ?

[PPatrick]

For OpenCL on CPU, it work.

Number of platforms: 1
Platform Profile: FULL_PROFILE
Platform Version: OpenCL 1.2 AMD-APP (923.1)
Platform Name: AMD Accelerated Parallel Processing
Platform Vendor: Advanced Micro Devices, Inc.
Platform Extensions: cl_khr_icd cl_amd_event_callback cl_amd_offline_devices


Platform Name: AMD Accelerated Parallel Processing
Number of devices: 2
Device Type: CL_DEVICE_TYPE_GPU
Device ID: 4098
Board name: ATI Mobility Radeon HD 4650
Device Topology: PCI[ B#1, D#0, F#0 ]
Max compute units: 8
Max work items dimensions: 3
Max work items[0]: 128
Max work items[1]: 128
Max work items[2]: 128
Max work group size: 128
Preferred vector width char: 16
Preferred vector width short: 8
Preferred vector width int: 4
Preferred vector width long: 2
Preferred vector width float: 4
Preferred vector width double: 0
Native vector width char: 16
Native vector width short: 8
Native vector width int: 4
Native vector width long: 2
Native vector width float: 4
Native vector width double: 0
Max clock frequency: 550Mhz
Address bits: 32
Max memory allocation: 134217728
Image support: No
Max size of kernel argument: 1024
Alignment (bits) of base address: 2048
Minimum alignment (bytes) for any datatype: 128
Single precision floating point capability
Denorms: No
Quiet NaNs: Yes
Round to nearest even: Yes
Round to zero: Yes
Round to +ve and infinity: Yes
IEEE754-2008 fused multiply-add: Yes
Cache type: None
Cache line size: 0
Cache size: 0
Global memory size: 536870912
Constant buffer size: 65536
Max number of constant args: 8
Local memory type: Global
Local memory size: 16384
Kernel Preferred work group size multiple: 32
Error correction support: 0
Unified memory for Host and Device: 0
Profiling timer resolution: 1
Device endianess: Little
Available: Yes
Compiler available: Yes
Execution capabilities:
Execute OpenCL kernels: Yes
Execute native function: No
Queue properties:
Out-of-Order: No
Profiling : Yes
Platform ID: 0x7fe716aaa0a0
Name: ATI RV730
Vendor: Advanced Micro Devices, Inc.
Device OpenCL C version: OpenCL C 1.0
Driver version: CAL 1.4.1720
Profile: FULL_PROFILE
Version: OpenCL 1.0 AMD-APP (923.1)
Extensions: cl_khr_gl_sharing cl_amd_device_attribute_query

[Dade]

For OpenCL on CPU, it work.

This may be the evidence of a problem inside the OpenCL GPU device driver.

Local memory type: Global
Local memory size: 16384

I haven't understood if you have tried only the QBVH accelerator or also the BVH. The (lack) of local GPU memory could be the source of your problem: BVH accelerator is a lot simpler than QBVH and it doesn't require local memory at all. It may work on your GPU.

[PPatrick]

even with the 3 structures, same error. I reinstall linux mint with 32 bits, same error ...

[Dade]

even with the 3 structures, same error. I reinstall linux mint with 32 bits, same error ...

PPatrick, I'm pretty sure the problem is in the HD4650 limited hardware resources and/or (lacking of) driver support. AMD has announced it will drop the support for HD4xxx family with Catalyst 12.6.

[PPatrick]

I think too.

Thanks for your help.