inline scanning code for fast distance computations#4785
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mdouze wants to merge 1 commit intofacebookresearch:mainfrom
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inline scanning code for fast distance computations#4785mdouze wants to merge 1 commit intofacebookresearch:mainfrom
mdouze wants to merge 1 commit intofacebookresearch:mainfrom
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Summary: After the ResultHandler diff landed there was a 1% performance regression on some critical codepath. It seems plausible that this regression was caused because the inner loop of the scanning code calls 2 virtual functions: - distance_to_code to compute a code distance - add_result to update the result structure whenever a better restlt is found It is probably the distance_to_code function that is the culprit because it is called for *all* the codes, when distance_to_code is called only if a better rresult is found. What this diff changes is that the scanning code is made available to the InvertedListScanner implementation so that the distance computation inlining can happen. This is applied to IndexIVFScalarQuantizer, IndexIVFFlat and IndexIVFRabitQ (it turns out that this one has a virtual function call inside its ditance_to_code so this update is unlikely to be significant). Reviewed By: junjieqi Differential Revision: D91830227
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This pull request has been merged in 851ce24. |
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Summary:
After the ResultHandler diff landed there was a 1% performance regression on some critical codepath.
It seems plausible that this regression was caused because the inner loop of the scanning code calls 2 virtual functions:
It is probably the distance_to_code function that is the culprit because it is called for all the codes, when distance_to_code is called only if a better rresult is found.
What this diff changes is that the scanning code is made available to the InvertedListScanner implementation so that the distance computation inlining can happen.
This is applied to IndexIVFScalarQuantizer, IndexIVFFlat and IndexIVFRabitQ (it turns out that this one has a virtual function call inside its ditance_to_code so this update is unlikely to be significant).
Reviewed By: junjieqi
Differential Revision: D91830227