[haiku-appserver] Re: CPU-idle-loop and HALT instruction?

On 2005-12-13 at 00:26:58 [+0100], Ingo Weinhold <bonefish@xxxxxxxxxxxxxxx> 
wrote:
> 
> On 2005-12-12 at 23:52:06 [+0100], Stephan Assmus <superstippi@xxxxxx> 
> wrote:
> > > > Or, is it already in there and can I somehow enable it?
> > > 
> > > From src/system/kernel/arch/x86/arch_cpu.c:
> > > 
> > > void
> > > arch_cpu_idle(void)
> > > {
> > >     switch (smp_get_num_cpus()) {
> > >         case 0:
> > >             panic("You need at least 1 CPU to run Haiku\n");
> > >         case 1:
> > >             asm("hlt");
> > >         default:
> > >             break;
> > >     }
> > > }
> > > 
> > > So, if you have more than one CPU, the only thing you can do is change
> > > this
> > > code. There might be a reason, why it is implemented like it is, though.
> > > On
> > > the other hand there's also no comment that you computer will explode 
> > > when
> > > executing "hlt" on a multi CPU machine either...
> > 
> > I seem to recall that on my dual CPU machine, there is simply two idle
> > threads running. Or is my memory failing me?
> 
> No. The question was, what the idle threads are executing, though. And 
> that's
> the above function (in an endless loop).

Yeah, but why would a person with more than one CPU have to change that code, 
if the real fix is making sure that there is simply as many idle threads as 
CPUs? (Somewhere else form this code.) Or am I totally confused?

Best regards,
-Stephan

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