ggml: fix zero division in ‘dne’ calculation in CUDA COUNT_EQUAL operator when ‘ne’ is small#10213
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JohannesGaessler merged 1 commit intoggml-org:masterfrom Nov 9, 2024
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The test-backend-ops with CUDA enabled failed, which is obvious. |
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Sorry, I thought the threshold at which this bug would occur with the test was 500 streaming multiprocessors (which would be much larger than any NVIDIA GPU currently available) but it's actually 125 which is less than is e.g. on an RTX 4090. Thanks for the patch. |
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…ator when ‘ne’ is small (ggml-org#10213)
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…ator when ‘ne’ is small (ggml-org#10213)
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When the total number of elements ne is smaller than 4 * nsm , the integer division ne / (4 * nsm) in the COUNT_EQUAL operator results in zero. This causes dne, which determines the data chunk size per thread block, to be zero. As a result, the CUDA kernel for the COUNT_EQUAL operator doesn’t execute correctly, leading to incorrect computation results.