From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anthony Liguori Subject: Re: KVM power usage - high wakeup rates Date: Thu, 19 Jun 2008 13:34:15 -0500 Message-ID: <485AA6A7.2060806@codemonkey.ws> References: Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org To: Haydn Solomon Return-path: Received: from wx-out-0506.google.com ([66.249.82.227]:44855 "EHLO wx-out-0506.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753862AbYFSSew (ORCPT ); Thu, 19 Jun 2008 14:34:52 -0400 Received: by wx-out-0506.google.com with SMTP id h29so260363wxd.4 for ; Thu, 19 Jun 2008 11:34:51 -0700 (PDT) In-Reply-To: Sender: kvm-owner@vger.kernel.org List-ID: 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) : extra timer interrupt > 4.9% (227.6) : Rescheduling interrupts > 1.6% ( 72.9) USB device 6-2 : Optical USB Mouse (Logitech) > 1.3% ( 61.7) : nvidia > 1.3% ( 59.0) : 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 > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >