Hi all,
I've just spent some time working on MIDI in Pd and have made it possible to send and receive MIDI sysex messages in Linux (sorry, this isn't possible in Windows or IRIX which make it much harder to do.) Use the "midiout", "midiin" and "sysexin" objects.
Also, a new parameter, "sleepgrain", allows you to specify how long Pd sleeps when it's idle; this is 1/4 of the audio buffer length by default. You can reduce MIDI time jitter by lowering this to, say, 2 msec. This on all OSes.
Finally, if you've noticed sluggish MIDI input, that should be improved now for Linux at least.
Go to http://lena.ucsd.edu/~msp/Software and grab "0.32TEST1-linux."
cheers Miller