Understand thread_sync_cost and framework_cost calculation in mkl_heuristics.h

I am trying to understand the mkl_heuristcs from tensorflow/core/util/mkl_heuristics.h .In rewrite_thresholds list the const values are given to framework cost and thread_sync_cost as :
{“Conv2D”, 0x41, 0xd40, {0.9349, 22.603}},
{“_FusedConv2D”, 0x41, 0xd40, {0.9349, 22.603}},
{“FusedBatchNormV3”, 0x41, 0xd40, {0.3223, -0.8822}},
{“Sigmoid”, 0x41, 0xd40, {0.0, 0.064736}}

Here how these constants are being calculated or taken into consider for rewrite thresholds?