core: ARM64 loop unrolling in kmeans to improve Weighted Filter performance #27596
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modules/core/src/kmeans.cpp
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| @@ -120,6 +120,20 @@ static void generateCentersPP(const Mat& data, Mat& _out_centers, | |||
| { | |||
| double p = (double)rng*sum0; | |||
| int ci = 0; | |||
| #if defined(_M_ARM64) | |||
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#if CV_ENABLE_UNROLLED should be checked too.
modules/core/src/kmeans.cpp
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| for (; ci + 1 < N - 1; ci += 2) | ||
| { | ||
| p -= dist[ci]; | ||
| if (p <= 0) break; |
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break doesn't provide the same result due to the next loop.
At least for p value.
Don't squash if body - separate lines are necessary for accurate reports of code coverage analyses.
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Hi @opencv-alalek,
- Reverted the earlier unrolling of the
ploop to maintain correctness, as you mentioned. - Increased the unrolling factor of the existing tdist2 accumulation loop to ×8, preserving original behavior while improving benchmark performance.
- I have updated the changes in this commit.
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This PR improves the performance of the Weighted Filter function from the ximgproc module on Windows on ARM64.
The optimization is achieved by unrolling two performance-critical loops in the generateCentersPP function in modules/core/src/kmeans.cpp, which is internally used by the Weighted Filter function.
The unrolling is enabled only for ARM64 builds using #if defined(_M_ARM64) guards to preserve compatibility and maintain performance on other architectures.
Performance Improvements: