Looks reasonable - let me see what can be done.
Thanks
Ralph
Greg Watson wrote:
Ok, thanks.
For clarification, the model we're using at the moment looks roughly
like this:
orte_init();
forever () {
if (do_our_stuff() == GAME_OVER)
break;
opal_event_loop(OPAL_EVLOOP_ONCE);
}
orte_finalize();
The simplest change for us would be something like:
orte_init();
forever () {
if (do_our_stuff() == GAME_OVER)
break;
if (opal_event_loop(OPAL_EVLOOP_ONCE) != ORTE_SUCCESS) {
clean_up_our_stuff();
break;
}
}
orte_finalize();
Greg
On Apr 20, 2006, at 10:21 AM, Ralph Castain wrote:
You make a good point about the library not
calling exit(). I'll have to recruit some help to look at the notion of
opal_even_loop returning an error value - it isn't entirely clear who
it would return it to in our system,. Even though I understand how
someone in your situation would handle it, I have to ensure that it
doesn't cause the base system problems, or force a major code revision
that would need to be scheduled into the project.
We'll have to get back to you on this - most of the folks are at a
workshop this week, so it will probably be next week before we can
discuss it.
Ralph
Greg Watson wrote:
The simplest thing for us would be for
opal_event_loop() to return an error value. That way we can detect the
situation and clean up our system. At the moment we're not trying to
restart orted, so clean recovery of orte is not that important, though
ultimately I would think it is desirable. Other alternatives are to
pass you an error handler that you call, or you could send a signal
that we can trap.
>From our perspective, we're simply calling a library that does
stuff. Having the library call exit() at any point is a major problem
for applications trying to do more than run a single job.
Greg
On Apr 20, 2006, at 9:40 AM, Ralph Castain wrote:
Well, I actually don't know much about
opal_event_loop and/or how it is intended to work. My guess is that:
(a) your remote orted is acting as the seed and your local process (the
one in Eclipse) is running as a client to that seed - at least, that
was the case last I talked to Nathan
(b) when the seed orted dies, it is the oob in your local client that
actually detects socket closure and decides that - since it is the seed
that has lost contact - the local application must abort.
(c) the errmgr.abort function does exactly what it was supposed to do -
it provides an immediate way of killing the local process.
I'd be a little hesitant to recommend overloading the errmgr.abort
function as you really do want the local processes to die when losing
connection to the seed (at least, until we develop a recovery
capability for the seed orted - which is some ways off), and (given the
way you are running) I'm not sure you can have a different errmgr for
your process while leaving the other one for everyone else.
Probably the best solution for now would be for us to insert a (yet
another) MCA parameter into the errmgr that would (if set) have
errmgr.abort do something other than exit. The question then is: what
would you want it to do?? We need to have it tell the rest of the
system to stop trying to send messages etc - right now, I don't think
the infrastructure exists to do that short of killing orte.
We could try to have errmgr.abort do an orte_finalize - that would kill
the orte system without impacting your host program, I suspect. You
would then have to re-initialize, so we'd have to find some way to let
you know that we had finalized. I can't swear this will work, though -
we might well generate a segfault since this is happening deep down
inside the system. We could try it, though.
Would any of that be of help? Do you have any suggestions on how we
might let you know that we had finalized?
Ralph
Brian Barrett wrote:
On Apr 19, 2006, at 4:15 PM, Greg
Watson wrote:
We've just run across a rather tricky
issue. We're calling opal_event_loop() to dispatch orte events to an
orted that has been launched separately. However if the orted dies for
some reason (gets a signal or whatever) then opal_event_loop() is
calling exit(). Needless to say, this is not good behavior us. Any
suggestions on how to get around this problem?
Is the orted you are connecting to the "seed" daemon? I think the only
time we should be exiting like that is if the orted was the seed
daemon. I'm not sure what we want to do if that's the case -- it looks
like we're calling errmgr.abort() when badness happens. I wonder if
your application can provide its own errmgr component that provides an
abort that doesn't actually abort? Just some off the cuff ideas --
Ralph could probably give a better idea of exactly what is happening...
Brian
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