Forum > GPU crunching
WUs that CUDA MB can't do correctly
popandbob:
A new error for you all to have fun with...
cudaAcc_find_triplets doesn't support more than MAX_TRIPLETS_ABOVE_THRESHOLD numBinsAboveThreshold in find_triplets_kernel
http://setiathome.berkeley.edu/result.php?resultid=1112071921
I didn't do stand alone testing due to my pc locked up every time I tried to....
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Raistmer:
This task has different online and standalone results for CUDA app.
standalone results for my build, stock 6.06 and CPUapp all strongly similar, online result gave overflow.
So, there is influence between tasks, not just temporal locality of bad tasks.
AR ~2.16
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Josef W. Segur:
--- Quote from: popandbob on 04 Jan 2009, 02:16:31 pm ---A new error for you all to have fun with...
cudaAcc_find_triplets doesn't support more than MAX_TRIPLETS_ABOVE_THRESHOLD numBinsAboveThreshold in find_triplets_kernel
http://setiathome.berkeley.edu/result.php?resultid=1112071921
I didn't do stand alone testing due to my pc locked up every time I tried to....
--- End quote ---
And the MAX_TRIPLETS_ABOVE_THRESHOLD constant is 10. I was wondering whether that would show up. It only allows for that many of the power samples to be above threshold in one Power over Time array, and those arrays are up to 128K samples in size. It is handled just like the case where more than one triplet is detected in one PoT array, a flag is set which causes a SETIERROR() call with the Unsupported Function code (12), which is negated by the time BOINC sees it (and because it's only defined in the SETI source, BOINC condiders it an unknown error).
It's a good protection from splitter problems like what happened when Enhanced first was released on main and again shortly after we started doing work from multibeam; the triplet threshold was much too low or even negative for some WUs. OTOH, it probably ought to be classed like result_overflow and be reported as a success if that's the purpose of setting the limit that low.
Joe
Raistmer:
It's all true if it would be show in CPU result too. While we have such error in GPU only I tend to think it's just another CUDA app problem....
Josef W. Segur:
--- Quote from: Raistmer on 04 Jan 2009, 05:11:10 pm ---It's all true if it would be show in CPU result too. While we have such error in GPU only I tend to think it's just another CUDA app problem....
--- End quote ---
In this case it looks like a design choice rather than an execution bug. My guess is someone did a mathematical estimation of the most "above threshold" points which should occur in pure random data and allowed for somewhat more. It looks like another case where ideal randomness isn't quite achieved...
Joe
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