ext/bcmath: Performance improvement bcsqrt()
#18771
Draft
+309
−52
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Test
Approximately 80 million calculations were performed using values of various magnitudes and scales, and all results matched those from the previous implementation.
Benchmark
Performance improvements are particularly noticeable in the following cases:
For large values that do not fall into the above categories, most of the execution time is spent on the iterative process of the Newton-Raphson method, especially on division operations. As a result, while there may be some minor gains from reducing memory allocations and lowering the cost of converting BCD to BC_VECTOR, there is no significant improvement in overall performance.
Small size value (fast path)
Code:
Result:
Middle size value (< 1) (standard path)
Code:
Result:
Middle size value 1 (fast path)
The new logic ignores unnecessary scales in the calculation, so this is a fast path.
Code:
Result:
Middle size value 2 (standard path)
Code:
Result:
Big size value (standard path)
Code:
Result: