Hi,
your answer surprises me a little. Up until now I thought that
Runtime.probe() unloads the current task (activity) from a thread, so
another task (activity) can use this thread and therefore I expected,
that the inner at (Place(0)) async {...} would be executed at some
point, even if this place has only one thread. What exactly does
Runtime.probe() do then?
Cheers,
Marco
Am 10.03.2015 um 13:47 schrieb David P Grove:
> Marco Bungart <m.bung...@gmx.net> wrote on 03/10/2015 05:11:27 AM:
> >
> > the appended program shows nondeterministic behaviour. Sometimes it
> > finishes, most times it runs into an endless loop. It happends with both
> > native and managed X10. I am using the repository revision 29129 of X10,
> > java 1.8.0_40 and gcc 4.8.2.
> > With an older version of X10 (2.4.3.2), the program terminates just fine.
> > One observation I was able to make: the program terminated only, if
> > X10_RESILIENT_MODE was set to 1. If it was unset, I was not able to
> > observe termination (but this could be pure coincidence...).
> >
> > Environment variables and compile-command used (command line parameter
> > only prevents flooding your console):
> >
> > $ >export X10_NPLACES=2 X10_NTHREADS=1
> > $ >x10c++ ../src/Hello.x10 -o Hello && ./Hello 5000000
> >
> > Could someone explain to me, what is going wrong or what changed?
> >
>
> Hi Marco,
>
> We'll take a look. But at first glance at your code and without running
> it, I would expect it to get into an infinite loop almost all the time.
> You have asked for 1 thread per place and you have the one thread in
> Place(0) spinning executing a busy wait loop. I suspect what has
> changed since 2.4.3.2 is that the runtime has gotten better at not
> having extra active threads, which in older versions may have provided
> the surplus execution resources in Place(0) to make this program not get
> stuck in the busy wait loop.
>
> The proper way to write this program would be to have the waiting
> activity be blocked on a when(plh().finished) and have the releasing
> activity do atomic plh().finished = true;
>
> --dave
>
>
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