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Date: Thu, 25 Jul 2013 14:32:59 +0200
From: Jan Kiszka <jan.kiszka@siemens.com>
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Subject: Re: [Qemu-devel] [RFC 0/8] arm AioContext with its own timer stuff
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To: Alex Bligh <alex@alex.org.uk>
Cc: Kevin Wolf <kwolf@redhat.com>, Stefan Hajnoczi <stefanha@redhat.com>, Stefan Hajnoczi <stefanha@gmail.com>, Liu Ping Fan <qemulist@gmail.com>, qemu-devel@nongnu.org, Anthony Liguori <anthony@codemonkey.ws>, Paolo Bonzini <pbonzini@redhat.com>

On 2013-07-25 14:21, Alex Bligh wrote:
> 
> 
> --On 25 July 2013 14:05:30 +0200 Stefan Hajnoczi <stefanha@gmail.com>
> wrote:
> 
>> Alex Bligh's series gives each AioContext its own rt_clock.  This avoids
>> the need for synchronization in the simple case.  If we require timer
>> access between threads then we really need to synchronize.
>>
>> You pointed out in another email that vm_clock stops when the guest is
>> paused.  I think we can find a solution for I/O throttling and QED,
>> which use vm_clock in the block layer.  Note that block jobs already use
>> rt_clock.
> 
> I would happily at a QEMUClock of each type to AioContext. They are after
> all pretty lightweight.

What's the point of adding tones of QEMUClock instances? Considering
proper abstraction, how are they different for each AioContext? Will
they run against different clock sources, start/stop at different times?
If the answer is "they have different timer list", then fix this
incorrect abstraction.

Jan

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