Re: [Qemu-devel] USB performance Question

[address@hidden]

Thanks Arnon.

USB1 works really great even for complex streaming cameras!
Although it is just very very slow.
As mentioned I only get about 10kbit/s! which is something I dont understand why.
I would have expected 1Mbit/s and could live with that.

If there are any test you want me to do please dont hesitate.

Cant wait for your USB2 implementation.
Great effort!




Arnon Gilboa wrote:

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