Re: [Qemu-devel] USB performance Question

[Arnon Gilboa]

I am in the middle of coding EHCI (USB 2.0) host controller emulation.
It is supposed to support faster device speeds (480 Mbit/sec instead of
USB 1.1 speeds - 1.5 or 12Mbit/sec). I will post it on the list when it
basicly supports simple devices such as disk-on-key. Currently I still
have some major problems with the scheduling of async and periodic frame
lists.

I will check your comment regarding the speed and see what can be done.
Anway, if you want to try to solve the issue yourself, the relevant code
is in usb-linux.c (Linux host USB redirector) and the USB UHCI/OHCI
controller emulations (hw/usb-uhci.c or hw/usb-ohci.c).

-----Original Message-----
From: address@hidden
[mailto:address@hidden On Behalf Of
address@hidden
Sent: Sunday, November 25, 2007 3:01 PM
To: address@hidden
Subject: Re: [Qemu-devel] USB performance Question

Does anyone have a comment about this?
It would be interesting to know where the USB development is going as it
is extremely promising and the only small obstacle (i.m.o) for full
feature device access.
The only remaining barrier is speed which should be improved.

I can look at the code if someone can point me to where in the sources
the USB interface is.

thanks


address@hidden wrote:
> I could get very complicated USB devices to work under Qemu with 
> Windows as guest, Linux as host.
> This is pretty amazing development and I must congratulate the Qemu 
> developers.
>
>
> The only problem is the USB speed.
> I get only about 10kbit/s max!
> This is measured by downloading a 1MByte scientific camera image.
>
>
> Is this the expected USB speed at the moment or is there anything I 
> can do to improve speed?
>
> Thanks
>
>
>
>