Re: high load with win7 & usb tablet

[Avi Kivity <avi@redhat.com>]

  On 09/10/2010 03:44 PM, Michael Tokarev wrote:
> 10.09.2010 16:19, Avi Kivity wrote:
>>   On 09/03/2010 03:21 PM, Michael Tokarev wrote:
>>> Hello.
>>>
>>> I noticed that window7, unlike windowsXP as I played with
>>> previously, poses quite high load on host when idle.  On
>>> my machine, host cpu usage is about 25% when one single-cpu
>>> win7 guest is running with "-usbdevice tablet" option.
>>> Here's a typical kvm_stats when such a guest is idling:
> []
>> That's pretty good for an idle guest.
> Hm.  Well.  Sometimes it goes "a bit" further than that:
>
>   efer_reload                  0       0
>   exits                  6307547   12445

This still isn't worth 25% cpu.

>> What does the guest think it is doing?  The Windows performance monitor?
> Nothing.  It shows perfmon.exe using 3% CPU, and that's about
> it.  I'm attaching a .png screenshot of the KVM window with
> w7 perfmon running.  Unfortunately I don't have English
> version handy, it's all in Russian, and I weren't able to
> change system language to English.  But it is still readable.
>
> During this shot, host CPU was about 30..35% in use - higher
> than usual 25%, but I guess it's due to perfmon.

Please build qemu with --disable-strip and use 'perf' to profile it.

> Also, I haven't found a way to see, for example, individual
> interrupt activity in windows (like /proc/interrupts in
> linux).

irq_injections is very low anyway.

-- 
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