On Mon, 14 Feb 2005 02:19 am, Jon Buller wrote:
> On 00 Jan 00 00:00:00,
>
> Berndt Josef Wulf wrote:
> > G'day,
> >
> > Where can I find benchtests performed for USB2 compliant controllers on
> > NetBSD-i386 that would give some indication on the expected maximum data
> > bandwidth? Currently, I'm only managing a maximum of 4MBytes/sec with a
> > Intel 82801DB USB EHCI Controller (rev. 0x01) connected to a Cypress
> > 7C63013 device (FX2), which is a long way off from its theoratical
> > 480Mbits/sec of a fullspeed USB2 interface.
>
> You meant high-speed USB interface, didn't you?  Full-speed is
> 10Mbits/sec (or is it 12?)  High-speed is the fast one.  I (and
> everyone else I know) thinks the USB people were on crack when they
> thought up those names.  If you really are configuring it at full speed,
> there is some chance for improvement there (2x or 3x), but not 100x.

The measured data bandwidth is 4MBytes/sec. This is only 10% of the maximum 
bandwidth theoretically achievable. Linux developers report data bandwidth of 
32-40MBytes/sec under the same conditions. 

Is there generic support for asynchronous reading and writing?  That
is, multiple reads and writes outstanding, which notifies
their completion? (Signals, polling, etc).

Is there a USB specific ioctl that allows submission of an USB "URB"
(USB Request Block) asynchronously?

Is there a way of improving data throughput on this device or is this the best 
we currently can do? Find below some kernel and userland messages on system 
configuration and performance.

./program_and_start.sh
Using device /dev/ugen0 on bus /dev/usb3 vendor id 0xfffe product id 0x0002
Read 102400000 bytes in 25 seconds and 1068 microseconds. Rate of 4095825 
bytes/second

 ehci0 at pci0 dev 29 function 7: Intel 82801DB USB EHCI Controller (rev. 
0x01)
 ehci0: interrupting at irq 11
 ehci0: EHCI version 1.0
 ehci0: companion controllers, 2 ports each: uhci0 uhci1 uhci2
 usb3 at ehci0: USB revision 2.0
 uhub3 at usb3
 uhub3: Intel EHCI root hub, class 9/0, rev 2.00/1.00, addr 1
 uhub3: single transaction translator
 uhub3: 6 ports with 6 removable, self powered

usbdevs -v
[,,,]
Controller /dev/usb3:
addr 1: high speed, self powered, config 1, EHCI root hub(0x0000), 
Intel(0x8086), rev 1.00
 port 1 addr 2: high speed, self powered, config 1, USRP Rev 2(0x0002), Free 
Software Folks(0xfffe), rev 1.02
 port 2 powered
 port 3 powered
 port 4 powered
 port 5 powered
 port 6 powered


-- 
Every man who says frankly and fully what he thinks is doing a public service.
[Leslie Stephen]