slow or even crash with CULAR14 linked MATLAB

General CULA Dense (LAPACK & BLAS) support and troubleshooting. Use this forum if you are having a general problem or have encountered a bug.

slow or even crash with CULAR14 linked MATLAB

Postby cscb_lab » Thu Mar 29, 2012 8:30 am

I just downloaded CULA dense R14, installed, set up environmental variables as blog said.
then tried test case matlab w/o CULA:
>>tic;N=4096;A=rand(N ); A=A*A'; A=A+diag(diag(A )*N); toc;
Elapsed time is 2.761875 seconds.
active another MATlab with CULA using matlab_cula.bat
>> tic;N=4096;A=rand(N);A=A*A';A=A+diag(diag(A)*N);toc;
Elapsed time is 1.195314 seconds.

It looks like the calculation speed doubled.

Then I increased N from 4096 to 10000, my monitor screen suddenly black for seconds, then error message pop up "Graphic driver does not work properly" and after waiting a little, it shows "Elapsed time is 39.195314 seconds."
while comparing when using Matlab w/o CULA, Elapsed time is 17.169872 seconds.

Anybody knows the reason or any suggestions for that?

My operation system is Win7, 64bit using Matlab 2011b.
GPU Properties:
Name: 'Quadro 5000'
Index: 1
ComputeCapability: '2.0'
SupportsDouble: 1
DriverVersion: 4.1000
MaxThreadsPerBlock: 1024
MaxShmemPerBlock: 49152
MaxThreadBlockSize: [1024 1024 64]
MaxGridSize: [65535 65535]
SIMDWidth: 32
TotalMemory: 2.6844e+009
FreeMemory: 2.4100e+009
MultiprocessorCount: 11
ClockRateKHz: 1026000
ComputeMode: 'Default'
GPUOverlapsTransfers: 1
KernelExecutionTimeout: 1
CanMapHostMemory: 1
DeviceSupported: 1
DeviceSelected: 1

Thanks and I appreciate.
Posts: 1
Joined: Wed Mar 28, 2012 1:59 pm

Re: slow or even crash with CULAR14 linked MATLAB

Postby john » Thu Mar 29, 2012 10:24 am

This can happen if you run long operations on the GPU to which the display is attached. I personally strongly prefer running my CUDA programs on a non-attached GPU. The problem on Windows is that the CUDA calls are processed first by the Windows graphics driver levels, which has a "feature" that kills and restarts the GPU if it thinks it has hung up. You can disable this, but it will result in your display freezing up during long CUDA computations such as this - you'll find that "watchdog timer" is the applicable keyword to include in your search.
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Joined: Thu Jul 23, 2009 2:31 pm

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