Optimise HLL union for mergeHLLtoHLL #572
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freakyzoidberg
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I vaguely remember when I worked on similar improvements I found that max is faster than comparison. My understanding is that branch prediction misses are expensive, and max can be implemented with no branches. |
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This PR introduce JMH benchmark - happy to remove it and leave that to characterisation if thats an issue.
This also only shows in a particular place that some optimisation can be gained by avoiding a call to Math.max + array mutation with a simple comparaison.
About 8% gain for HLL heap union
Before
After