Hi Marco - the short answer is that Team.x10, as well as Clocks, are not
yet resilient-aware. If a place dies while using either of these, you may
get unexpected behavior, at least in the upcoming 2.5.0 release.
- Ben
From: Marco Bungart <m.bung...@gmx.net>
To: x10-users@lists.sourceforge.net
Date: 09/17/2014 08:59 AM
Subject: [X10-users] Place.places() and Team.allreduce(...)
Hi there,
I am playing around with the current svn-version (R28225). In
particular, I tried using allreduce in combination with Place.places.
Example code is appended. I was able to make the following observations:
- The behaviour of the code changes with X10_NPLACES.
- The behaviour of the code changes with the place, which died.
- The behaviour is (partially) non-deterministic.
I tested the code under Ubuntu linux (14.04), gcc 4.8.3 and openJDK
1.7.0_65. I summarized my results in the table below.
I compiled the program with both the C++- and the Java-Backend. Both
show the same behaviour.
| ID of killed Place (args(0)):
NPLACES | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
2 | P | | | | | | |
4 | ok | P | P | | | | |
8 | ok | S/2 | S/2 | P | P | P | P |
"P" means: premature program abortion.
The output can take one of tow forms: a short one and a long one.
short:
$ ./Hello 2
x10.lang.DeadPlaceException: DeadPlaceException at Place(2)
Place 2 exited unexpectedly with exit code: 1
Launcher 2: cleanup complete, exit code=1. Goodbye!
Launcher 0: cleanup complete, exit code=1. Goodbye!
long:
$ ./Hello 3
x10.lang.DeadPlaceException: DeadPlaceException at Place(3)
Place 3 exited unexpectedly with exit code: 1
Launcher 3: cleanup complete, exit code=1. Goodbye!
Launcher 1: cleanup complete, exit code=1. Goodbye!
at
x10::lang::FinishResilientPlace0::addDeadPlaceException
(x10::lang::FinishResilientPlace0__State*,
long long)
at x10::lang::FinishResilientPlace0::quiescent(long long)
at x10::lang::FinishResilientPlace0::notifyPlaceDeath()
at x10::lang::FinishResilient::notifyPlaceDeath()
at x10::lang::Runtime::notifyPlaceDeath()
at x10::lang::Runtime__Pool::scan(x10::util::Random*,
x10::lang::Runtime__Worker*)
at x10::lang::Runtime__Worker::loop()
at x10::lang::Runtime__Worker::__apply()
at x10::lang::Thread::thread_start_routine(void*)
at GC_inner_start_routine
at GC_call_with_stack_base
at GC_start_routine
at
at clone
Place(0): Place.places():
Launcher 0: cleanup complete, exit code=1. Goodbye!
Launcher -1: cleanup complete, exit code=1. Goodbye!
"S" means program gets stuck, the output looks like this:
$ ./Hello 3
x10.lang.DeadPlaceException: DeadPlaceException at Place(3)
at
x10::lang::FinishResilientPlace0::addDeadPlaceException
(x10::lang::FinishResilientPlace0__State*,
long long)
at x10::lang::FinishResilientPlace0::quiescent(long long)
at x10::lang::FinishResilientPlace0::notifyPlaceDeath()
at x10::lang::FinishResilient::notifyPlaceDeath()
at x10::lang::Runtime::notifyPlaceDeath()
at x10::lang::Runtime__Pool::scan(x10::util::Random*,
x10::lang::Runtime__Worker*)
at x10::lang::Runtime__Worker::loop()
at x10::lang::Runtime__Worker::__apply()
at x10::lang::Thread::thread_start_routine(void*)
at GC_inner_start_routine
at GC_call_with_stack_base
at GC_start_routine
at
at clone
Place(0): Place.places():
Place(0)
Place(1)
Place(2)
Place(4)
Place(5)
Place(6)
Place(7)
Place(0): stage 1.
Place 3 exited unexpectedly with exit code: 1
(still running)
"S/2" meaning "getting stuck about half of the time, running as expected
half of the time", showing non-deterministic behaviour.
Is there something wrong with the way I use broadcast/allreduce or are
the corresponding library-functions still under construction for X10 2.5.0?
Cheers,
Marco
[attachment "Hello.x10" deleted by Benjamin Herta/Watson/IBM]
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