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Re: [Qemu-devel] [PATCH] uhci: Lower uhci timer freq when guest is idle
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From: |
Gerd Hoffmann |
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Subject: |
Re: [Qemu-devel] [PATCH] uhci: Lower uhci timer freq when guest is idle |
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Date: |
Wed, 26 Mar 2014 08:58:57 +0100 |
On Mi, 2014-03-26 at 11:57 +0800, address@hidden wrote:
> From: Gonglei <address@hidden>
>
> UHCI emulation polls the device at a freq of 1000HZ, which consumes
> 12~13% CPU even though a Windows guest is completely idle when the guest
> was configed usb1.1 tablet devcie. This solution counts accumulated NAK
> packets. when it reaches to 64, then the guest is supposed to be idle
> and the freq is lowered to 10HZ.
>
> This patch has been tested on Win7/WinXP/Win2008 guests, that reduces
> the CPU consume from 12~13% to 6~7%.
Which qemu version did you test with? With any 2.0 release candidate
windows guests should suspend the usb-tablet. And possibly stop all usb
polling done by the uhci controller in case the tables is the only
device connected.
So this should not be needed any more.
cheers,
Gerd