On Saturday 01 July 2006 16:24, Thierry Herbelot wrote: > Le Saturday 1 July 2006 15:31, Hans Petter Selasky a écrit : > > Yes, but don't forget high-speed USB transfers. They require larger > > buffers. For example 1024 bytes for ULPT is too little. The interrupt > > rate will be so high, that it is unrealistic to transfer 20MB/s using > > 1024 byte interrupts. My rewritten ULPT now uses "2*(1<<17)" buffers. > > Hello, > > I wonder what kind of speed you are getting
It depends much on the equipment you are using. For example I have a Brother USB 2.0, Laser Printer, postscript compatible, and if I were to guess, it eats something like 1MB/s. On the other hand I tested with an external USB 2.0, 2.5" IDE adapter, and it transfers around 20MB/s. > : I would like to see improvements for reads (and writes) on > standard endpoints, without having to resort to writing specific > drivers (using ugen on the standard FreeBSD USB stack). > > One goal would be to achieve something like 25 to 30 Mbytes/s, sustained, > (finally getting to some interesting fraction of the peak USB2 data rate). I don't think that will be a problem, as long as you use large enough buffers. A buffer of 1/50 th of the transfer rate should suffice, from my experience. --HPS _______________________________________________ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "[EMAIL PROTECTED]"
