qjackctl is a pretty old piece of ancient software :) those numbers are just there since ages ago.
and you're correct, N is the number of xrus as detected from scraping the messages log and it only applies to the alsa backend (the most usual perhaps), while M is the number of xruns actually reported through jack api (ie. counts the number of xrun callbacks issue by the jack subsystem).
i guess new users have to live with all these qjackctl idiosyncrasies though.
qjackctl is a pretty old piece of ancient software :) those numbers are just there since ages ago.
and you're correct, N is the number of xrus as detected from scraping the messages log and it only applies to the alsa backend (the most usual perhaps), while M is the number of xruns actually reported through jack api (ie. counts the number of xrun callbacks issue by the jack subsystem).
i guess new users have to live with all these qjackctl idiosyncrasies though.
don'rt worry, be happy :)
byee