Does it help to run PD using nice? e.g. 'nice -5 pd' and jack with a priority of 70 or so?
i doubt that ... pd is not a proper jack client, just renicing doesn't really help. the best latency i could achieve with the modified scheduler in pd, that tries to make pd a proper jack client.
if I use -jack in my pdrc then -rt does nothing, right? I thought -rt wsa for alsa opperation.
of you use pd with -rt, it will try to give pd realtime capabilities ... but this doesn't really help, if jack doesn't have realtime capabilities.
if you need lowest latencies, i'd recommend, you check out devel, since it reduces the latency by one io block size ...
but there are some design decisions in pd (it's better in devel, but still not optimal), that will _never_ allow pd to become a very low latency system...
cheers ... tim