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From: Paolo Bonzini <pbonzini@redhat.com>
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Date: Mon, 11 Jan 2016 09:22:08 +0100
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Subject: Re: [Qemu-devel] QEMU/KVM performance gets worser - high load -
 high interrupts - high context switches
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To: Gerhard Wiesinger <lists@wiesinger.com>, qemu-devel@nongnu.org



On 09/01/2016 17:46, Gerhard Wiesinger wrote:
> 
> # Positive consequences via munin monitoring:
> # Reduced fork rate: 40 => 13
> # process states: running 15 => <1
> # CÜU temperature: (core dependant) 65-70°C => 56-64°C
> # CPU usage: system: 47% => 15%, user: 76% => 50%
> # Context Switches: 20k => 7.5k
> # Interrupts: 16k => 9k
> # Load average: 2.8 => 1
> 
> => back at the level before one year!!!!!!!
> 
> Any idea why the serial device/PCI controller and the USB mouse tablet
> consume so much CPU on latest kernel and/or qemu?

For USB, it's possible that you're not using the USB autosuspend
feature?  (As explained in Gerd's blog post, for Microsoft OSes you may
need to fiddle with the registry).

For virtio-serial, I have no idea.

Paolo