If I'm just using SDL, does usb tablet provide any benefit?

On Thu, Jun 19, 2008 at 2:34 PM, Anthony Liguori <[EMAIL PROTECTED]> wrote:
> Haydn Solomon wrote:
>>
>> Hi List,
>>
>> When testing power usage of a windows xp guest using powertop utility,
>> I'm noticing high wakeup rates. The following is the output of
>> powertop for an idle windows xp guest.
>>
>>
>> ==============================
>> ===========================
>> Wakeups-from-idle per second : 2716.6   interval: 10.0s
>> no ACPI power usage estimate available
>>
>> Top causes for wakeups:
>>  52.4% (2434.4)   qemu-system-x86 : sys_timer_settime (posix_timer_fn)
>>  21.5% (996.7)   qemu-system-x86 : __kvm_migrate_pit_timer (pit_timer_fn)
>>  15.0% (697.4)       <interrupt> : extra timer interrupt
>>   4.9% (227.6)      <kernel IPI> : Rescheduling interrupts
>>   1.6% ( 72.9)   USB device  6-2 : Optical USB Mouse (Logitech)
>>   1.3% ( 61.7)       <interrupt> : nvidia
>>   1.3% ( 59.0)       <interrupt> : uhci_hcd:usb4, uhci_hcd:usb6, HDA Intel
>> ===================================================================
>>
>> I'm getting similar values when running a Fedora 9 guest.
>>
>> My host is running F9. Details of my /proc/cpuinfo :
>>
>> processor    : 1
>> vendor_id    : GenuineIntel
>> cpu family    : 6
>> model        : 15
>> model name    : Intel(R) Core(TM)2 Duo CPU     T7500  @ 2.20GHz
>> stepping    : 10
>> cpu MHz        : 2201.000
>> cache size    : 4096 KB
>> physical id    : 0
>> siblings    : 2
>> core id        : 1
>> cpu cores    : 2
>> fpu        : yes
>> fpu_exception    : yes
>> cpuid level    : 10
>> wp        : yes
>> flags        : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge
>> mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe
>> syscall nx lm constant_tsc arch_perfmon pebs bts rep_good pni monitor
>> ds_cpl vmx est tm2 ssse3 cx16 xtpr lahf_lm ida
>> bogomips    : 4387.73
>> clflush size    : 64
>> cache_alignment    : 64
>> address sizes    : 36 bits physical, 48 bits virtual
>> power management:
>>
>> The linux image I'm running is Linux localhost.localdomain
>> 2.6.25.4-30.fc9.x86_64 #1 SMP Wed May 21 17:34:18 EDT 2008 x86_64
>> x86_64 x86_64 GNU/Linux
>>
>> I'm starting my vm using the following command:
>>
>> /usr/local/kvm/bin/qemu-system-x86_64 \
>> -hda windowsxp.img \
>> -m 650 \
>> -localtime \
>> -net user \
>> -net nic,model=e1000 \
>> -smb /home/hsolomon \
>> -std-vga \
>> -soundhw all \
>> -usb \
>> -usbdevice tablet \
>> -name StandardPC-NAT &
>>
>
> USB tablet polls a lot.  You'll probably see far less wake ups if you don't
> use the tablet.
>
> With the default options, my idle winxp guest causes about 550 wakeups/sec
> which is pretty close to what I'd expect.  I don't think you'll get much
> better than that without using a dynticks guest.
>
> Regards,
>
> Anthony Liguori
>
>> Thanks
>>
>> Haydn
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>
>
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