Use raft::copy in the inner loop of the host-side raft::gather #2464
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achirkin
added
enhancement
achirkin
added
improvement
|
Converting this to a draft until we properly benchmark the change. |
tarang-jain
reviewed
Oct 8, 2024
tarang-jain
reviewed
Oct 8, 2024
| for (IdxT k = 0; k < buff.extent(1); k++) { | ||
| buff(i, k) = dataset(in_idx, k); | ||
| } | ||
| raft::copy(res, |
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So the resource is actually unused since the src and dest are both in host mem? I wonder if we can create a resource on the fly and supply it to raft::copy() rather than adding the resource to gather_buff's signature.
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Use
raft::copyinstead of an assignment operator loop in the host-side gather operation. This should allow to leverage the logic ofraft::copyto use fast memcpy when possible (especially for high-dimensional datasets).As some very circumstantial evidence, this change is observed to reduce
raft::matrix::sample_rows(100000000, 128)time from approximately 5 to 4 minutes (bigann-100M int8 dataset in RAM, 16-core machine).Make the NVTX annotations a little bit more descriptive along the way.