From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Zhang Haoyu" <zhanghy@sangfor.com>
Subject: Re: [question] lots of interrupts injected to vm when pressing somekey w/o releasing
Date: Tue, 25 Nov 2014 09:54:00 +0800
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References: <201411201020560455720@sangfor.com>,
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Cc: "Alex Williamson" <alex.williamson@redhat.com>,
	"Zhang, Yang Z" <yang.z.zhang@intel.com>,
	"Michael S.Tsirkin" <mst@redhat.com>,
	"Gleb Natapov" <gleb@cloudius-systems.com>
To: "Paolo Bonzini" <pbonzini@redhat.com>, "kvm" <kvm@vger.kernel.org>
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>>> Hi all,
>>>
>>> If I press the one of "Insert/Delete/Home/End/PageUp/PageDown/UpArrow/
>>> DownArrow/LeftArrow/RightArrow" key w/o releasing, then lots of interrupts
>>> will be injected to vm(win7/win2008), about 8000/s, the system become very slow,
>>> bringing very bad experience. But the other keys are okay.
>> 
>> Sorry for wrong description, the interrupt rate is normal, 
>> but huge numbers of vmexit induced by PIO were produced.
>
>This is expected when running Windows without paravirtualized time
>counter (-cpu ...,hv_time).
>
I tested win-server-2008 with "-cpu core2duo,hv_spinlocks=0xffff,hv_relaxed,hv_time",
this problem still happened, about 200,000 vmexits per-second, 
bringing very bad experience, just like being stuck.

Thanks,
Zhang Haoyu

>Paolo