SparkTransportConf is…​FIXME

Creating TransportConf

  _conf: SparkConf,
  module: String,
  numUsableCores: Int = 0): TransportConf


fromSparkConf is used when…​FIXME

Calculating Default Number of Threads

  numUsableCores: Int): Int

defaultNumThreads calculates the default number of threads for both the Netty client and server thread pools that is 8 maximum or numUsableCores is smaller. If numUsableCores is not specified, defaultNumThreads uses the number of processors available to the Java virtual machine.

8 is the maximum number of threads for Netty and is not configurable.