warning: the freebsd monitor

Cheng's monitor uses mtx_trylock to get the lock.
So, it might miss some samples if the lock is by other pipes. In this case, the the average/max/min will be not accurate.

Now Linux has the "abc" option in 2.6.16

This option is set to "on" by default which allows the window to grow as quick as if there were no delay ack...
good feature though:)