[Mpi-22] reConfigurable MPI
treumann at [hidden]
Thu Jul 1 10:32:04 CDT 2010
Most discussion I have heard relates to how a running job that makes a
decision, at a well defined point, to grow itself can do that. The MPI
standard currently tries to cover the aspects of this which fit within a
library model and leave the resource manager outside the standard.
This does not seem to be your focus. Tell me if I have misunderstood.
You seem to be interested in the situation where resources are added to a
cluster (or maybe freed up by other jobs completing) and having a running
MPI job get notified asynchronously that there are newly available
resources it can make a bid for. This idea of the cluster manager pushing
resources to a job without regard to where the job is in its execution
would bring lots of new issues. I am not aware of anybody having made a
serious attempt to even define what would be needed inside the MPI standard
to let applications catch and act on an asynchronous notification like
My first guess is that pushing an offer of additional resource would not be
very hard to design into a resource manager but the MPI API side of how to
react asynchronously to that offer would be very complex.
Either way (Running job decides to try for more resource vs resource
manager tries to volunteer more resource to running job) I think the MPI
standard can not try to specify very much about how the resource manager
does its part.
Dick Treumann - MPI Team
IBM Systems & Technology Group
Dept X2ZA / MS P963 -- 2455 South Road -- Poughkeepsie, NY 12601
Tele (845) 433-7846 Fax (845) 433-8363
> As you said, That paragraph is in the context of process creating
> and yes! my question was about runtime reconfiguration of an MPI
> cluster (whole) based on dynamic application requirements. But I
> think that would be impossible without having a flexible resource
> control. When a new node joins a cluster some pre-works must be done
> to enable that new node act as a member of that cluster (in run
> time), also, some one must be informed about new resources which
> just have been added to the cluster by entrance of new node and I
> think all these preparations need that missing flexible resource manager.
> mpi-22 mailing list
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