In jackdmp "async" mode (when the server does not wait for the graph
end in a given cycle but use output buffer computed the previous
cycle), there is up to one buffer more latency in the system.
On OSX (starting on Tiger) a property of the driver (called
kAudioDevicePropertyIOCycleUsage) allows to setup "how much of the
client portion of the IO cycle the process will use". Since the jack
server async mode does a "constant in time" computation at each cycle
(read input buffer, write output buffers from the previous cycle,
activate the graph), one can safely use this
kAudioDevicePropertyIOCycleUsage to a value < 1. The result is that
the output buffer size is lowered internally in the driver and the
overall latency can be reduced.
I guess a similar mechanism could be used in the ALSA driver. How can
the output buffer size be lowered at the driver level to achieve the