Paralellize the filling on the std::vector in DMatrix #41
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wphicks
reviewed
Feb 11, 2025
| data_ = std::vector<ElementType>{data_ptr, data_ptr + num_elem}; | ||
| data_.reserve(num_elem); | ||
| #pragma omp parallel for | ||
| for (std::uint64_t i = 0; i < num_elem; ++i) { |
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Do we have benchmarks showing the impact of this change at various scales? How often is this code likely to get called inside a block that is already parallelized? You mentioned this was a bottleneck; can you give an example of a workload where it is a bottleneck?
wphicks
reviewed
Feb 11, 2025
| @@ -17,6 +17,8 @@ def py_str(string): | |||
| """Convert C string back to Python string""" | |||
| return string.decode("utf-8") | |||
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| def check_if_fast(): | |||
| return True | |||
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Not sure if there's missing code here or if this was supposed to be removed before the PR was made.
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Currently the DMatrix creation is a bottleneck in the library because is not performed in parallel. This small modification can solve the issue and I am sure that it can be done also in more clean and performing way (e.g. playing with omp chunking).