Open MPI logo

Open MPI Development Mailing List Archives

  |   Home   |   Support   |   FAQ   |   all Development mailing list

Subject: Re: [OMPI devel] RFC: usnic BTL MPI_T pvar scheme
From: Christopher Samuel (samuel_at_[hidden])
Date: 2013-11-22 20:06:15


-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On 16/11/13 02:00, Jeff Squyres (jsquyres) wrote:

> This actually raises a point that MPI_T makes you read individual
> pvars separately -- there's no "atomically read this array of
> pvars" functionality. That could lead to inconsistent results
> (e.g., first you read a network stat, and then you read an MPI
> layer stat -- but under the covers, the network stat could have
> changed by the time you read the MPI layer stat). Hmm.

I suspect there's not much of a way around this, other than pausing
all MPI operations until you've read a value back from the OS. But
then if you want to read multiple values from the OS you're going to
be out of luck there too. Unless I'm missing something?

So perhaps the best thing is to just document this prominently.

All the best,
Chris
- --
 Christopher Samuel Senior Systems Administrator
 VLSCI - Victorian Life Sciences Computation Initiative
 Email: samuel_at_[hidden] Phone: +61 (0)3 903 55545
 http://www.vlsci.org.au/ http://twitter.com/vlsci

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.14 (GNU/Linux)
Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/

iEYEARECAAYFAlKP/4cACgkQO2KABBYQAh/ZPwCgkdZA184I9S3q0lwzBMJAB+lM
JAIAnA5iVFlXHAdTt+au5SIgsUBJ4pka
=0mM0
-----END PGP SIGNATURE-----