On 07/17/2012 04:50 PM, Orion Poplawski wrote:
While staring at top on my SL6 kvm server waiting for it to crash, I
noticed
that my idle Fedora kvm guests appear to be consuming between 8-12% cpu while
my idle SL6 guests appear to be consuming between 0.3-2% cpu as shown in the
qemu-kvm processes in top. In fact I have a Fedora 17 instance running now
with nothing but kernel processes and the qemu-kvm process still shows it
using 7-8% cpu.
Does anyone have any insight as to why this would be the case?
It appears that toggling the Autosuspend for USB device QEMU USB Tablet
[QEMU 0.12.1] tunable has a big effect and brings it in line with SL6.
SL6:
usb 1-1: Product: QEMU USB Tablet
input: QEMU 0.12.1 QEMU USB Tablet as
/devices/pci0000:00/0000:00:01.2/usb1/1-1/1-1:1.0/input/input4
generic-usb 0003:0627:0001.0001: input,hidraw0: USB HID v0.01 Pointer [QEMU
0.12.1 QEMU USB Tablet] on usb-0000:00:01.2-1/input0
# cat /sys/devices/pci0000:00/0000:00:01.2/usb1/1-1/power/autosuspend
2
# cat /sys/devices/pci0000:00/0000:00:01.2/usb1/1-1/power/level
auto
F17:
[ 3.015642] usb 1-1: Product: QEMU USB Tablet
[ 3.117125] input: QEMU 0.12.1 QEMU USB Tablet as
/devices/pci0000:00/0000:00:01.2/usb1/1-1/1-1:1.0/input/input3
[ 3.117827] generic-usb 0003:0627:0001.0001: input,hidraw0: USB HID v0.01
Pointer [QEMU 0.12.1 QEMU USB Tablet] on usb-0000:00:01.2-1/input0
# cat /sys/devices/pci0000:00/0000:00:01.2/usb1/power/autosuspend
2
# cat /sys/devices/pci0000:00/0000:00:01.2/usb1/1-1/power/level
on
So it appears that SL6 is setting to auto automatically, but Fedora is not. I
wonder why.
--
Orion Poplawski
Technical Manager 303-415-9701 x222
NWRA, Boulder Office FAX: 303-415-9702
3380 Mitchell Lane orion(a)nwra.com
Boulder, CO 80301
http://www.nwra.com