Re: USB EHCI patch for 0.14.0?

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

David Ahern wrote:
>
>
> On 03/09/11 14:28, Erik Rull wrote:
>> David Ahern wrote:
>> I've tried it long time ago with kvm-88, but there it was working but
>> extremely slow. (At least the mouse was reacting there)
>
> I thought you tried the EHCI patch against a recent qemu-kvm version --
> like December 2010 or January 2011.

Yes, this time I patched against 0.14.0, I misunderstood your question, sorry.
My last attempt before that was kvm-88.

>> Hm, okay.
>> As far as I understood it, the auto-add feature should be similar to the
>> USB 1.1, right? It seems to work basically but not fully - the system is
>> somehow slowed down, maybe the polling timer is too fast? (I will play a
>> little bit with that and review and compare as well the auto routine)
>>
>> And the usb-tablet should be an uhci-emulated component, that should
>> then not interfere with the ehci-emulation, right?
>
> My proposal from July 2010 was to have emulated devices state their
> version and have host devices try EHCI then UHCI. This means that the
> tablet device is attached to UHCI and a host USB key is attached to
> EHCI. Like this:
>
> info usb
>    Device 0.1, Port 1, Speed 12 Mb/s, Product QEMU USB Tablet
>    Device 1.1, Port , Speed 480 Mb/s, Product DT 101 II
> (qemu)
>
> That's what the patch I sent does.
>
> EHCI does have a lot higher frame rate and in its current form does have
> a noticeable impact on CPU usage when devices are connected and one of
> the lists is activated. If the OS deactivates the controller when there
> is nothing to do (e.g., not actively talking to the device), cpu usage
> goes down.

Thanks for the explanation!

> I just tried a few scenarios with the X and V versions of those GUI
> based guests and an external key attached to EHCI bus worked fine and
> the usb tablet also worked fine.
>
> I did notice some differences in command syntax. For instance, my
> scripts still use the older -usbdevice tablet syntax and I did not see
> the USB stall message. Switching to '-device usb-tablet' did generate
> the message at boot (though overall it seems to be harmless).
>
> Nothing fancy with the setup -- ide drive, virtio or e1000 networking,
> ac97 sound, no-hpet and usb tablet devices.
>
> In the time it took to write this response about 900MB was transferred
> to the usb key at about 1.7-1.8MB/sec rate.
>
> David

I will give it another try tomorrow. I use
-usb -device usb-tablet -device usb-host
The last parameter for the auto-add to the guest
I will also try the old parameter syntax.
What does the no-hpet option do? Might this be somehow significant 
regarding the performance?

Best regards,

Erik

P.S.
When EHCI was active today without tablet and without auto-add I got a 
transfer rate of ~5MByte/sec from USB key to the HDD.