QJackCtl shows 2 numbers for xruns (as I understand it, I could be completely wrong) like this : N (M) . My dim understanding from seeing an email post of yours, is that the left one, N, is an approximation obtained by searching some Jack log file or something, and the one in (M) is from Jack directly (not sure) and is more accurate. In any case, I observe that M > N, often by a large amount, which fits in with the approximation theory. However, if N is really some approximation, and (M) is the true value, why not remove N from the display? It is confusing, especially to new users, to have both numbers displayed when only the right one matters. On the other hand if N and (M) are measures of 2 different things it would be nice to know what they are. Thanks. QJackCtl is a very useful application, I use it all the time.