[Qemu-devel] Re: [PATCH 11/19] use a bottom half to run timers

[Michael S. Tsirkin]

On Tue, Jan 05, 2010 at 06:23:34PM +0300, malc wrote:
> On Tue, 5 Jan 2010, Michael S. Tsirkin wrote:
> 
> > On Mon, Jan 04, 2010 at 05:54:13PM -0600, Anthony Liguori wrote:
> > > On 01/04/2010 02:01 PM, Michael S. Tsirkin wrote:
> > >> On Mon, Jan 04, 2010 at 02:24:53PM -0600, Anthony Liguori wrote:
> > >>    
> > >>> On 12/21/2009 02:09 AM, Paolo Bonzini wrote:
> > >>>      
> > >>>> Make the timer subsystem register its own bottom half instead of
> > >>>> placing the bottom half code in the heart of the main loop.  To
> > >>>> test if an alarm timer is pending, just check if the bottom half is
> > >>>> scheduled.
> > >>>>
> > >>>> Signed-off-by: Paolo Bonzini<address@hidden>
> > >>>>        
> > >>> I'm not a huge fan of this for a couple reasons.  The first is that it
> > >>> introduces a subtle semantic change.  Previously, timers always ran
> > >>> before bottom halves whereas after this change, timers may run after
> > >>> some bottoms halves but before others.  While this should be okay in
> > >>> principle, in practice, I'm sure it'll introduce regressions.  I'd be
> > >>> very surprised if cris wasn't affected by this.
> > >>>
> > >>> But more importantly, I think timer dispatch needs to be part of the
> > >>> select loop.  malc has a git tree that replaces host alarm timers with
> > >>> select() timeouts.
> > >>>      
> > >> Where is that tree?
> > >>    
> > >
> > > http://repo.or.cz/w/qemu/malc.git  mtloop
> > 
> > Don't seem to see anything there.
> > malc?
> 
> Yes?

Do you have a patch to switch from signals to select?  If yes could you
tell me where it is so  I can test whether it fixes winxp install
crashes I see?


> > >> IMO we need that, I am not sure all code is as signal-safe
> > >> as it should be. At least crashes that I saw with winxp install
> > >> seem to be related to signal handling.
> > >>    
> > >
> > > Regards,
> > >
> > > Anthony Liguori
> > 
> 
> -- 
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