I'd like to track the rate of packet loss for outbound packets from some production servers. Obviously, that's impossible. But I think that the rate of TCP retransmissions should be a close proxy for packet loss. Currently I can only observe TCP retransmissions by using wireshark, a slow and laborious process. But it seems to me that the network stack should already have that information. Would it be possible to add a sysctl to expose the total number of retransmissions since boot? This information would be very useful. It could reveal for example problems with a model of NIC, or congestion on one network segment but not another, or a regression in the OS.
-Alan
