Re: [Qemu-devel] [RFC][PATCH] Add HPET emulation to qemu (v2)

[Samuel Thibault <samuel.thibault@ens-lyon.org>]

Anthony Liguori, le Sat 02 Aug 2008 09:46:30 -0500, a écrit :
> Samuel Thibault wrote:
> >Beth Kon, le Sat 02 Aug 2008 06:05:14 -0500, a écrit :
> >  
> >>I was trying to reproduce the wakeup every 10ms that 
> >>Samuel Thibault mentioned, thinking the HPET would improve it. 
> >>But for an idle guest in both cases (with and without HPET), the 
> >>number of wakeups per second was relatively low (28).
> >>    
> >
> >I was referring to vl.c's timeout = 10; which makes the select call
> >use a timeout of 10ms. That said, "/* If all cpus are halted then wait
> >until the next IRQ */", so maybe that's why you get slower wakeups per
> >second.  I'm still surprised because of the call to qemu_mod_timer in
> >pit_irq_timer_update which should setup at least a 100Hz timer with
> >linux guests (when they don't have HPET available).
> >  
> 
> The patch disables that when hpet is active.

That's why I would expect, indeed, but he is reporting that _without_
HPET he gets low wakeups per second already.

Samuel