[Qemu-devel] Re: [PATCH] fix halt emulation with icount and CONFIG_IOTHREAD

[Marcelo Tosatti <mtosatti@redhat.com>]

On Tue, Feb 15, 2011 at 07:58:53PM +0100, Jan Kiszka wrote:
> On 2011-02-15 18:54, Marcelo Tosatti wrote:
> > 
> > Note: to be applied to uq/master.
> > 
> > In icount mode, halt emulation should take into account the nearest event when sleeping.
> > 
> > Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
> > Reported-and-tested-by: "Edgar E. Iglesias" <edgar.iglesias@gmail.com>
> > 
> > diff --git a/cpus.c b/cpus.c
> > index 468544c..21c3eba 100644
> > --- a/cpus.c
> > +++ b/cpus.c
> > @@ -770,7 +770,7 @@ static void qemu_tcg_wait_io_event(void)
> >      CPUState *env;
> >  
> >      while (all_cpu_threads_idle()) {
> > -        qemu_cond_timedwait(tcg_halt_cond, &qemu_global_mutex, 1000);
> > +        qemu_cond_timedwait(tcg_halt_cond, &qemu_global_mutex, qemu_calculate_timeout());
> 
> checkpatch.pl would complain here.
> 
> More important: Paolo was proposing patches to eliminate all those fishy
> cond_wait timeouts. That's probably the better way to go. The timeouts
> only paper over missing signaling.
>
> >      }
> >  
> >      qemu_mutex_unlock(&qemu_global_mutex);
> > diff --git a/vl.c b/vl.c
> > index b436952..8ba7e9d 100644
> > --- a/vl.c
> > +++ b/vl.c
> > @@ -1335,7 +1335,7 @@ void main_loop_wait(int nonblocking)
> >      if (nonblocking)
> >          timeout = 0;
> >      else {
> > -        timeout = qemu_calculate_timeout();
> > +        timeout = 1000;
> >          qemu_bh_update_timeout(&timeout);
> >      }
> >  
> 
> Isn't this path also relevant for !IOTHREAD? What's the impact of this
> change for that configuration?

Timeout changes from 5s to 1s.