Re: [Qemu-devel] [PATCH 6/6] usb-tablet: Allow connecting to ehci

["Hao Luo"<luo_brian@126.com>]

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Erik,

You can take a look at my recent post about usb tablet peforamnce over ehci, in which I mentioned a libvirt config of how to let usb tablet connect to ehci.

2012-12-26



Hao Luo



发件人：Erik Rull
发送时间：2012-12-26 20:08
主题：Re: [Qemu-devel] [PATCH 6/6] usb-tablet: Allow connecting to ehci
收件人："Gerd Hoffmann"<kraxel@redhat.com>
抄送："Hans de Goede"<hdegoede@redhat.com>,"qemu-devel"<qemu-devel@nongnu.org>

Hi Gerd, hi Hans, 

is my assumption correct that if I check out and compile this version from  
GIT master that the usb-tablet device is automatically routed to ehci  
without changing anything else in the qemu call arguments? (And the  
performance enhancement takes place automatically) 
If not - what has to be changed to get it working? 

Best regards, 

Erik 



Gerd Hoffmann wrote: 
> From: Hans de Goede <hdegoede@redhat.com> 
> 
> Our ehci code has is capable of significantly lowering the wakeup rate 
> for the hcd emulation while the device is idle. It is possible to add 
> similar code ot the uhci emulation, but that simply is not there atm, 
> and there is no reason why a (virtual) usb-tablet can not be a USB-2 device. 
> 
> Making usb-hid devices connect to the emulated ehci controller instead 
> of the emulated uhci controller on vms which have both lowers the cpuload 
> for a fully idle vm from 20% to 2-3% (on my laptop). 
> 
> An alternative implementation to using a property to select the tablet 
> type, would be simply making it a new device type, ie usb-tablet2, but the 
> downside of that is that this will require libvirt changes to be available 
> through libvirt at all, and then management tools changes to become the 
> default for new vms, where as using a property will automatically get 
> any pc-1.3 type vms the lower cpuload. 
> 
> [ kraxel: adapt compat property for post-1.3 merge ] 
> 
> Signed-off-by: Hans de Goede <hdegoede@redhat.com> 
> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com> 
> 
> tablet compat fixup 
> 
> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com> 

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