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ansoncat
Journeyman III

HelloCL get segmentation fault on CPU

Hi,

On my computer, the sample program HelloCL get segmentation fault while running on a CPU device.

Here are output messages:


HelloCL!

Getting Platform Information

Creating a context AMD platform

Getting device info

Loading and compiling CL source

Segmentation fault

Segmentation fault is gone when I try to use GDB to debug it.

I have no idea what may happened.

Testing environment I used : 

Ubuntu 10.10 32-bit + Stream SDK 2.2/2.3 + Core i5 520M + Geforce 310M (nvidia ICD is removed)

Here are info dump by CLInfo:

 


 

Number of platforms: 1

  Platform Profile: FULL_PROFILE

  Platform Version: OpenCL 1.1 ATI-Stream-v2.3 (451)

  Platform Name: ATI Stream

  Platform Vendor: Advanced Micro Devices, Inc.

  Platform Extensions: cl_khr_icd cl_amd_event_callback cl_amd_offline_devices

  Platform Name: ATI Stream

Number of devices: 1

  Device Type: CL_DEVICE_TYPE_CPU

  Device ID: 4098

  Max compute units: 4

  Max work items dimensions: 3

    Max work items[0]: 1024

    Max work items[1]: 1024

    Max work items[2]: 1024

  Max work group size: 1024

  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: 2400Mhz

  Address bits: 32

  Max memory allocation: 536870912

  Image support: No

  Max size of kernel argument: 4096

  Alignment (bits) of base address: 1024

  Minimum alignment (bytes) for any datatype: 128

  Single precision floating point capability

    Denorms: Yes

    Quiet NaNs: Yes

    Round to nearest even: Yes

    Round to zero: Yes

    Round to +ve and infinity: Yes

    IEEE754-2008 fused multiply-add: No

  Cache type: Read/Write

  Cache line size: 64

  Cache size: 32768

  Global memory size: 1073741824

  Constant buffer size: 65536

  Max number of constant args: 8

  Local memory type: Global

  Local memory size: 32768

  Kernel Preferred work group size multiple: 1

  Error correction support: 0

  Unified memory for Host and Device: 1

  Profiling timer resolution: 1

  Device endianess: Little

  Available: Yes

  Compiler available: Yes

  Execution capabilities:  

    Execute OpenCL kernels: Yes

    Execute native function: Yes

  Queue properties:  

    Out-of-Order: No

    Profiling : Yes

  Platform ID: 0xb74fcb80

  Name: Intel(R) Core(TM) i5 CPU       M 520  @ 2.40GHz

  Vendor: GenuineIntel

  Driver version: 2.0

  Profile: FULL_PROFILE

  Version: OpenCL 1.1 ATI-Stream-v2.3 (451)

  Extensions: cl_amd_fp64 cl_khr_global_int32_base_atomics cl_khr_global_int32_extended_atomics cl_khr_local_int32_base_atomics cl_khr_local_int32_extended_atomics cl_khr_byte_addressable_store cl_khr_gl_sharing cl_ext_device_fission cl_amd_device_attribute_query cl_amd_media_ops cl_amd_popcnt cl_amd_printf 

 


 

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7 Replies
himanshu_gautam
Grandmaster

the system requirement for running openCL are mentioned here:

http://developer.amd.com/gpu/ATIStreamSDK/pages/DriverCompatibility.aspx

 

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Himanshu, are you sure? I think that if do not run on GPU, ATI stream doesn't require Catalyst drivers. I am sure that I could run the samples (on CPU) while I was using open-source radeon X driver (and didn't have path to /usr/lib/fglrx/* in LD_LIBRARY_PATH, or even not the Catalyst installed).

EDIT: Supposing that other system requirements are trivially satisfied (eg. in Ubuntu 10.10 is default gcc 4.4 which is ok). Or do you think it's because of Intel processor?
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I have seen some other post reporting problem with ubuntu 10.10. This OS is not mentioned in Supported OSes list.Have you tried on some listed OS?

OpenCL should work on CPU without Catalyst and i am not aware of any issues with intel CPUs either.

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I have tested it on Win 7 64bit on the same machine.

Both 32 and 64 bit of Stream SDK are Ok with windows.

As Himanshu said, it may be somthing wrong with ubuntu 10.10.
I guess it is related to threads since the problem is gone while GDB using libthread_db to monitor/management the HelloCL.

 

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> As Himanshu said, it may be somthing wrong with ubuntu 10.10.
I am not sure of that - I think that Ubuntu 10.10 is fine, at least for me (although I am using 64 bit flavour). There may be someone that has problems but I wouldn't blame Ubuntu 10.10 - take that definitely some tens of percent of Linux users here are using 10.10 so it is natural, that someone has problems but I don't think it is common.
The reason why is supported 10.04 and not 10.10 is in my opinion that 10.04 is LTS (with long support). Not because of problems of 10.10. But I can be wrong.
> I guess it is related to threads since the problem is gone while GDB using libthread_db to monitor/management the HelloCL.
It may be true, actually I don't know how gdb manages threads. BTW, are you using SDK downloaded from AMD web or those deb packages by nou? In the latter case I would suggest to compile/link the examples by yourself.
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Hi,

I'm using  SDK from AMD web.

I plan to try it on ubuntu 10.10 64 bit later.

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I may have found solution of you problem:
I guess you have nvidia drivers, don't you. And the problem might be, that the driver contains incompatible libOpenCL (don't ask why incompatible - maybe because it is 1.0 and ati stream has 1.1?) Try to force to use ATI Stream's libOpenCL. (If you haven't already done so. Otherwise is this post irrelevant.)

I tried to simulate (perhaps your) situation:
martin@minerva:/usr/src/ati-stream-sdk-v2.3-lnx64/samples/opencl/bin/x86_64$ LD_LIBRARY_PATH=/usr/lib64/nvidia-current/:/usr/src/ati-stream-sdk-v2.3-lnx64/lib/x86_64 ./HelloCL
./HelloCL: /usr/lib/nvidia-current/libOpenCL.so: no version information available (required by ./HelloCL)
HelloCL!
Getting Platform Information
Creating a context AMD platform
Getting device info
Loading and compiling CL source
Segmentation fault

On the other hand, running with gdb and those environment variables succeded (output is a bit verbose so I won't paste it), similarly to what you wrote.

this alseo succeeded:
martin@minerva:/usr/src/ati-stream-sdk-v2.3-lnx64/samples/opencl/bin/x86_64$ LD_LIBRARY_PATH=/usr/src/ati-stream-sdk-v2.3-lnx64/lib/x86_64 ./HelloCL
HelloCL!
Getting Platform Information
Creating a context AMD platform
Getting device info
Loading and compiling CL source
Running CL program
Done
Passed!

EDIT: If you think it might help don't forget to re-link the examples against ATI libs
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