Open MPI logo

Open MPI Development Mailing List Archives

  |   Home   |   Support   |   FAQ   |   all Development mailing list

From: gshipman (gshipman_at_[hidden])
Date: 2007-05-17 14:40:06


>
> The fork() problem is due to memory registration aggravated by
> registration cache. Memory registration in itself is a hack from
> the OS
> point of view, and you already know a lot about the various problems
> related to registration cache.
>
So Gleb is indicating that this is a problem in the pipeline protocol
which does not use a registration cache. I think the registration
cache, while increasing the probability of badness after fork, is not
the culprit.

> The right way to fix the fork problem is to fix the memory
> registration
> problem in the OS itself. It's not going to happen anytime soon, so it
> requires another hack (forcing VM duplication of registered pages at
> fork time).
>
> Patrick
> --
> Patrick Geoffray
> Myricom, Inc.
> http://www.myri.com
> _______________________________________________
> devel mailing list
> devel_at_[hidden]
> http://www.open-mpi.org/mailman/listinfo.cgi/devel