Open MPI logo

Open MPI Development Mailing List Archives

  |   Home   |   Support   |   FAQ   |  

This web mail archive is frozen.

This page is part of a frozen web archive of this mailing list.

You can still navigate around this archive, but know that no new mails have been added to it since July of 2016.

Click here to be taken to the new web archives of this list; it includes all the mails that are in this frozen archive plus all new mails that have been sent to the list since it was migrated to the new archives.

Subject: Re: [OMPI devel] [OMPI svn-full] svn:open-mpi r22762
From: Iain Bason (Iain.Bason_at_[hidden])
Date: 2010-03-03 14:06:53


On Mar 3, 2010, at 1:24 PM, Jeff Squyres wrote:

> I'm not sure I agree with change #1. I understand in principle why the change was made, but I'm uncomfortable with:
>
> 1. The individual entries now behave like pseudo-regexp's rather that strict matching. We used strict matching before this for a reason. If we want to allow regexp-like behavior, then I think we should enable that with special characters -- that's the customary/usual way to do it.

The history of this particular piece of code is that it used to use strncmp. George Bosilca changed it last summer, incidental to a larger change (r21652). The commit comment was not particularly illuminating on this issue, in my opinion:

http://www.open-mpi.org/hg/hgwebdir.cgi/ompi-svn-mirror/rev/bde31d3db7ba

> 2. All other <foo>_in|exclude behavior in ompi is strict matching, not prefix matching. I'm uncomfortable with the disparity.

That turns out not to be the case. Look in btl_tcp_proc.c/mca_btl_tcp_retrieve_local_interfaces.

> Additionally, if loopback is now handled properly via change #2, shouldn't the default value for the btl_tcp_if_exclude parameter now be empty?

That's a good question. Enabling the "lo" interface results in intra-node messages being striped across that interface in addition to the others on a system. I don't know what impact that would have, if any.

> Actually -- thinking about this a little more, does opal_net_islocalhost() guarantee to work on peer interfaces?

It looks to see whether the IP address is (v4) 127.0.0.1, or (v6) ::1. I believe that these values are dictated by the relevant RFCs (but I haven't looked to make sure).

Iain