Hi Experts,
I am debugging the WordCount Flink streaming program in local mode. Flink version is 1.7.2
I saw the following calculation logic about network buffer in class TaskManagerServices.
jvmHeapNoNet is equal to -xmx amount in Java.
why the networkBufBytes = xmx / (1-networkBufFraction) * networkBufFraction, it is a bit strange.
why it is not calculated by xmx * networkBufFraction?
 
final long networkBufBytes = Math.min(networkBufMax, Math.max(networkBufMin,
(long) (jvmHeapNoNet / (1.0 - networkBufFraction) * networkBufFraction)));

Best 
Henry