Robert craig
|
Re: RE: RE: Network throughput test
|
Robert craig
08/19/2009 3:22 PM
post36325
|
Re: RE: RE: Network throughput test
My recollection of the BSD based USB drivers was that they weren't the best for speed. They have a low number of rx and
tx descriptors (believe it or not, the default is 1 (yup, ONE) of each). I seem to remember that it's pretty easy to
up the Rx descriptor types, but the Tx required a little bit of extra work (you can take a look at the axe driver source
to see what was done to increase the descriptors for 6.4.1). For the URAL driver, these are defined in sys/dev/usb/
if_uralvar.h.
That being said, the BSD drivers also go through a BSD - QNX conversion layer and that layer definitely introduces a
performance penalty. A native driver will run faster. You can take a look at the devnp-axe (BSD) driver versus devn-
asix to get an idea of what a BSD ported USB driver is like when compared to a QNX written driver (and note that devn-
asix is an old-style io-net driver and not a native io-pkt style driver).
R.
|
|
|