[tx] increase timeres on TX pressure and reduce log noise

when TX sockets are overloaded, we spend more time spitting out
logs than recovering from the overload. ifdef the logging on
critical path out (still available with debug build).

also drastically reduce the waiting time by 64x.

this changes increases UDP perf on 3 nodes by 200%

Signed-off-by: Fabio M. Di Nitto <fdinitto@redhat.com>