Investigate possibility of reducing CPU utilization

[mrnuke]

It was reported by @grobian that realtek-poe appears to use more CPU time than other comparable daemons. realtek-poe seems to run arund 1.0% to 1.3%.

My suspicion is that we're waking up every time a byte comes in. We might want to tune the VMIN and VTIME termios parameters. The purpose of this issue is to keep track of any testing, and report the findings.