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P2P performance with nccl-tests vs nvbandwidth #268

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goelayu opened this issue Nov 19, 2024 · 1 comment
Open

P2P performance with nccl-tests vs nvbandwidth #268

goelayu opened this issue Nov 19, 2024 · 1 comment

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@goelayu
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goelayu commented Nov 19, 2024 •
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I would assume that nvbandwidth's device_to_device_memcpy_write_sm test should report somewhat comparable bandwidth to nccl-tests's sendrecv_perf. If that assumption is incorrect, any explanation as to why would be appreciated?

If the assumption is correct, I am seeing vastly different numbers on my setup. 2 H100s connect via NVLink. nvbandwidth reports 260GB/s whereas sendrecv_perf reports somewhere around 80GB/s for the default configuration.

Sweeping message sizes from 4K to 4G, and the bandwidth increases from 80 to 180 GB/s but seems to plateau thereafter.
@aruhela
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aruhela commented Jan 10, 2025

Did you find any answer to your query?

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@aruhela @goelayu