I run on ARM v5 (Pogo E02 and mobile) two applications that request continuously serial converters. One app is write in c (aurora) and the other is in python (pyserial).
I notice the pooling is worst on raspberry (I tried Pl2303 and FT232), i can only achieve a pooling each 2-3 sec and i've got often communication errors. On my ARMv5 i used to refresh around each second without hitch.
What's wrong with the Raspberry ? Is there anything i can change to make it more fast and reliable ? I already try to put dwc_otg.speed=1 (speed of USB 1.1) but it wasn't really better.