Some FeynCalc routines can be parallelized meaning that the code will try to distribute chunks of the calculation to multiple Mathematica kernels.
To this aim the number of subkernels should roughly correspond to the number of CPU cores
To enable the parallelization you need to actively launch some
parallel kernels and then set the variable
$ParallelizeFeynCalc to True. In this case a
copy of FeynCalc will be loaded on each of the parallel kernels and used
to parallelize some selected operations. For example,
LaunchKernels[8]
$ParallelizeFeynCalc = TrueFCLoopFromGLIFCFeynmanPrepareFCLoopToPakFormFCLoopFindIntegralMappings