Optimize unionfind cache locality. - #438
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This patch interleaves node parent and size to improve cache locality. With this, accessing parent[i] and size[i] hits the same cache line instead of arrays that are MBs apart arrays. Signed-off-by: iabdalkader <i.abdalkader@gmail.com>
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This patch interleaves node parent and size to improve cache locality. With this, accessing parent[i] and size[i] hits the same cache line instead of arrays that are MBs apart. Note this change wouldn't make any difference on machines with MBs of cache, however on MCUs with a few KBs of cache, it shows a significant difference.
I've tested this on both real hardware (STMN6 Cortex-M55) and Arm's FVP (Fixed Virtual Platform) by running AprilTag on one of the test images 100 times and averaging run times. The results show ~5-6% speedup: