Sampler's begin for callee's null check before fence (less overhead in corner case) #253
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This improves performance in the case there is no callee for the kokkosp_begin_parallel_for. This is actually done correctly in the kokkosp_begin_parallel_scan and begin_parallel_reduce.
masterleinad
approved these changes
May 20, 2024
Thanks! Applying clang-format today. |
Done. |
crtrott
approved these changes
May 23, 2024
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This PR is simple fix involving a slight reduction in Kokkos Tools runtime overhead for one of the kokkosp_begin_parallel_xyz callbacks (done correctly for the other two); it does not raise any incorrect behavior in the develop branch version of the sampler. The callee being null is a corner case, and this reduces overhead in that case.
Specifically, in the function
kokkosp_begin_parallel_for(), the check of the callee pointer being null is placed after the tool-invoked fence. It should be placed before the tool-invoked fence. If the child callee pointer is null, e.g., the sampler's tool-invoked fence need not be invoked. This would reduce Kokkos Tools runtime overhead.Note that this is consistent with @(DavidPoliakoff)'s passthrough utility draft PR.