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From: Peter Maydell <peter.maydell@linaro.org>
Date: Thu, 13 Feb 2014 17:04:38 +0000
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Subject: Re: [Qemu-devel] timer issue on 1.7.0 and later
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To: Alex Bligh <alex@alex.org.uk>
Cc: Paolo Bonzini <pbonzini@redhat.com>, Rob Herring <robherring2@gmail.com>, QEMU Developers <qemu-devel@nongnu.org>

On 13 February 2014 16:31, Alex Bligh <alex@alex.org.uk> wrote:
> The current code (timer_mod_ns_locked) runs the rearm code
> if the modified timer is at the front of the timer queue
> (only). So if you modify B (in your example above) whether
> you extend or reduce the time, it will only 'rearm' if
> B now occurs before A. However, if you modify A, it will
> currently rearm whether you reduce the expiry time of
> A (correct) or whether you extend it so long as it doesn't
> now expire after B (this could perhaps be optimised).
>
> So it's not quite as bad as you think.

A little experimentation with the debugger for an SMP
A9 guest suggests this may be a red herring anyway. Once
it's got started, the only thing that was causing calls
to timerlist_notify was the GUI, and if you run with
-display none we don't call timerlist_notify at all
at the point where we seem to be stalling.

thanks
-- PMM