From mboxrd@z Thu Jan  1 00:00:00 1970
From: Dor Laor <dor.laor@qumranet.com>
Subject: Re: [patch 0/3] fix PIT injection
Date: Wed, 30 Jul 2008 00:50:06 +0300
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Cc: Avi Kivity <avi@qumranet.com>, Sheng Yang <sheng.yang@intel.com>,
	kvm <kvm@vger.kernel.org>
To: Marcelo Tosatti <mtosatti@redhat.com>
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Marcelo Tosatti wrote:
> The in-kernel PIT emulation can either inject too many or too few
> interrupts.
>
>   
While it's an improvement, the in-kernel pit is still not perfect. For 
example, on pit frequency changes the
pending count should be recalculated and matched to the new frequency. I 
also tumbled on live migration problem
and there is your guest smp fix.
IMHO we need to switch back to userspace pit. [Actually I did consider 
in-kernel pit myself in the past.]. The reasons:
1. There is no performance advantage doing this in the kernel.
    It's just potentially reduced the host stability and reduces code
2. There are floating patches to fix pit/rtc injection in the same way 
the acked irq is sone here.
    So the first 2 patches are relevant.
3. Will we do the same for rtc? -> why duplicate userspace code in the 
kernel?
    We won't have smp issues since we have qemu_mutex and it will be 
simpler too.

If you agree, please help merging the qemu patches.
Otherwise argue against the above :)

Cheers, Dor