Last 3 days I saw a lot of connection lost (drops) in the logs and it caused the miner to crash/restart. Can someone explain to me what are em (eminer) and fm (fminer)? Thanks

03:52:26:824   68   watchdog - eminer thread hangs
03:52:26:824   68   em hbt: 194234, fm hbt: 15,
03:52:26:824   68   Miner thread hangs, need to restart miner!