[Vm-dev] Re: Where does process preemtion takes place?

Guillermo Polito guillermopolito at gmail.com
Mon Dec 10 17:44:28 UTC 2012


Nope, I mean preempting. When my process has the priority and is the active
process, it gets preempted by higher priority processes. But my process
does not make any #yield.

On Mon, Dec 10, 2012 at 5:21 PM, Bert Freudenberg <bert at freudenbergs.de>wrote:

>
>
> On 2012-12-10, at 16:39, Guillermo Polito <guillermopolito at gmail.com>
> wrote:
>
> > But somehow if I run
> >
> > [ [true] whileTrue: [ Transcript show: 'asd'; cr.] ] fork.
> >
> > It gets preempted while it is running, and It does not make any yield...
>
> You did not ask about user interrupt handling specifically before.
> "Preempting" means any suspending of a lower-priority process by a
> higher-priority one.
>
> Pressing the interrupt key sets the interruptPending flag, which signals
> TheInterruptSemaphore (see checkForInterrupts). This resumes the interrupt
> watcher process.
>
> - Bert -
>
> >
> > On Mon, Dec 10, 2012 at 4:17 PM, Bert Freudenberg <bert at freudenbergs.de>
> wrote:
> >
> > On 2012-12-10, at 14:22, Guillermo Polito <guillermopolito at gmail.com>
> wrote:
> >
> > > Hi!
> > >
> > > I was looking at the process machinery in VMMaker and I can't find
> where the preemption of processes takes place...
> > >
> > > Can someone point me a place?
> >
> > It happens in #transferTo:. This is called whenever a process is resumed
> because a semaphore got signaled (in which case the process that was
> waiting on the semaphore is resumed) or if the process stops working
> because of a wait / yield / suspend call (in which case
> #wakeHighestPriority determines the next process).
> >
> > - Bert -
> >
> > PS: no need to send a mail to both vm-dev and vm-beginners :)
> >
> > _______________________________________________
> > VM-beginners mailing list
> > VM-beginners at lists.squeakfoundation.org
> > http://lists.squeakfoundation.org/mailman/listinfo/vm-beginners
> >
>
>
>
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