Re: [Qemu-devel] Re: [PATCH] fix smp with tcg mode and --enable-io-thread

[Anthony Liguori]

On 06/23/2010 02:42 AM, Jan Kiszka wrote:
> Jan Kiszka wrote:
>    
> > Marcelo Tosatti wrote:
> >      
> > > On Mon, Jun 21, 2010 at 10:58:32PM +0200, Jan Kiszka wrote:
> > >        
> > > > Jan Kiszka wrote:
> > > >          
> > > > > Marcelo Tosatti wrote:
> > > > >            
> > > > > > Clear exit_request when iothread grabs the global lock.
> > > > > >
> > > > > > Signed-off-by: Marcelo Tosatti<address@hidden>
> > > > > >
> > > > > > diff --git a/cpu-exec.c b/cpu-exec.c
> > > > > > index 026980a..74cb973 100644
> > > > > > --- a/cpu-exec.c
> > > > > > +++ b/cpu-exec.c
> > > > > > @@ -236,10 +236,8 @@ int cpu_exec(CPUState *env1)
> > > > > >       asm("");
> > > > > >       env = env1;
> > > > > >
> > > > > > -    if (exit_request) {
> > > > > > +    if (exit_request)
> > > > > >           env->exit_request = 1;
> > > > > > -        exit_request = 0;
> > > > > > -    }
> > > > > >              
> > > > > Coding style...
> > > > >
> > > > >            
> > > > > >   #if defined(TARGET_I386)
> > > > > >       if (!kvm_enabled()) {
> > > > > > diff --git a/cpus.c b/cpus.c
> > > > > > index fcd0f09..ef1ab22 100644
> > > > > > --- a/cpus.c
> > > > > > +++ b/cpus.c
> > > > > > @@ -598,6 +598,7 @@ void qemu_mutex_lock_iothread(void)
> > > > > >           }
> > > > > >           qemu_mutex_unlock(&qemu_fair_mutex);
> > > > > >       }
> > > > > > +   exit_request = 0;
> > > > > >   }
> > > > > >
> > > > > >   void qemu_mutex_unlock_iothread(void)
> > > > > >
> > > > > >
> > > > > >              
> > > > > I looked into this a bit as well, and that's what I also have in my
> > > > > queue.
> > > > >
> > > > > But things are still widely broken: pause_all_vcpus and run_on_cpu as
> > > > > there is no guarantee that all VCPUs regularly call into
> > > > > qemu_wait_io_event. Also breakpoints don't work, not only in SMP mode.
> > > > >            
> > > This fixes pause for me:
> > >
> > >        
> > Partially. It caused regressions on the SMP scheduling without the early
> > loop exit in my patch. I will break up my changes later today and post
> > them as series.
> >      
> After fixing the APIC/IOAPIC fallouts, the series is almost done.
> Unfortunately, host&guest debugging is totally broken for
> CONFIG_IOTHREAD (I also noticed that [1] is still not merged).

Did it not get applied to uq/master or has there just not been a merge 
request yet?

Regards,

Anthony LIguori

>   I will
> try to fix this first as it may require some more refactorings.
>
> Jan
>
> [1] http://thread.gmane.org/gmane.comp.emulators.kvm.devel/52718
>
>