Just very preliminary results:
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1. Sti  base line CpuTot/tracks = 0.0537394

2. Stv base line CpuTot/tracks = 0.143779

3. Stv old KNN  CpuTot/tracks = 0.189489

4. Stv improved KNN CpuTot/tracks = 0.130533

5. StvKnn no hft seeds CpuTot/tracks = 0.111291
Summary:
 new KNN improved by 10%
 new KNN better than base line Stv by 9%
 base line Stv  slower than Sti 2.6 times
 new KNN still slower than Sti 2.4 times
StvKnn with no HFT seeds slower than Sti 2.1 times

This result for only few impovement of KNN.