Upon further investigation I found that in Ardour's Jack latency menu, the "frames/period" DO in fact match up with the number in qjackctl. What showed a confusing half-value was Ardour's "output latency" display (always half the milliseconds shown in Jack). The XRUNS I saw were probably just due to Ardour requiring twice the latency of other jack programs. So, to me, this behavior is actually not a bug. Nothing to fix.
However, there was another Ardour latency-related bug in 9.11 that was fixed in Ardour 2.8.8 (http://ardour.org/node/3384). So, as long as Gazpacho uses at least 2.8.8, should be good.
Upon further investigation I found that in Ardour's Jack latency menu, the "frames/period" DO in fact match up with the number in qjackctl. What showed a confusing half-value was Ardour's "output latency" display (always half the milliseconds shown in Jack). The XRUNS I saw were probably just due to Ardour requiring twice the latency of other jack programs. So, to me, this behavior is actually not a bug. Nothing to fix.
However, there was another Ardour latency-related bug in 9.11 that was fixed in Ardour 2.8.8 (http:// ardour. org/node/ 3384). So, as long as Gazpacho uses at least 2.8.8, should be good.