Re: [Qemu-devel] USB 2.0 printer passthrough very slow

[Erik Rull <erik.rull@rdsoftware.de>]

Hi,

Reeted wrote:
> On 04/03/12 15:33, Erik Rull wrote:
>> Hi,
>>
>> please try to use the .cfg file from the docs/ directory,
>
> The ich9-ehci-uhci.cfg ? Yes it's the same thing I am using.
> If you look at the <qemu:commandline> section I have replicated that file
> exactly.
> I had access rights problem using the .cfg file, that's why I replicated it
> in the commandline, but it's the same thing really.

You're right.

>> using this file, the USB printer speed is really good on my systems. Well
>> it is still an emulation so you'll never get native speed, but it is far
>> better than the USB 1.x emulation we had in 0.1x versions.
>> Best thing to test the approx. transfer speed: Plug in a fast usb key,
>> copy some larger data chunks and measure the time - on the same port
>> where you attach the printer.
>
> I had tested that on a linux guest and it was 6.5MB/sec (dd streaming of
> the device! Not file copy) as I said, but you are right, it's better if I
> try it on the real windows guest. I won't have a chance to test it until
> the weekened though.
>
>>
>> Printing e.g. the Windows XP test page takes not really more time than on
>> a native system.
>
> And if you send a second job it follows the first one right away or it
> takes minutes in between?

Hm, I didn't have an eye on that, but I don't see any reasons why the USB 
speed should slow down the Windows Printing Queue.

> What printer?

Tested with an EPSON USB 2.0 and a HP with USB 1.1.

> What qemu version?

I'm not sure which version is the oldest where it worked, but the current 
git master seems to be fine...
If you have no chance to get direct GIT access you can download the master 
from the git web interface as .tgz.

> Any chance you could post here your commandline? (from ps aux )

Currently not - the system is not available this week - sorry.

> What's the guest setting in device management, is it ACPI Uniprocessor
> http://www.neowin.net/forum/uploads/post-9158-1134631266.png
> or ACPI Multiprocessor or Standard PC or other?
> Mine is ACPI Multiprocessor with 2vCPU. Other settings were almost twice
> slower in booting the system.

Standard PC - I don't think that this is related to your issue.
Best thing would be to test it on a native system.
Well - Speeding up the system with a second core should increase the speed :-)

> (Sorry for the many questions :-) )
>
> Thanks for your help
> R.
>

Best regards,

Erik