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Subject: Re: [hwloc-devel] Something lighter-weight than XML?
From: Marcelo Alaniz (malaniz_at_[hidden])
Date: 2011-09-01 19:36:17


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On Thu, Sep 01, 2011 at 05:49:33PM +0200, Brice Goglin wrote:
> Did you actually find many machines/distribs that don't have libxml2
> installed by default? There are literaly hundreds of packages that depend
> on libxml2 (at least in Debian) so I am not sure depending on it is really
> a problem.
>
> Also are there really some string space problems? Even when talking about
> 1000 nodes transferring 100kB once at the beginning on the job, it doesn't
> look too bad to me (and these XMLs could be cached on the frontend as long
> as the compute nodes don't change).
>
> Otherwise, implementing this is likely easy, especially if you find
> somebody to do it :) Start from the XML export, convert it into a text
> export, and write the corresponding import (starting from the XML import
> may be hard because it's recursive).
>
> Would you need an export to a file or to a memory buffer or both?
>
> Last but not least: what's the deadline?
>
> Brice
>
> Le 01/09/2011 17:30, Jeff Squyres a ecrit :
>
> We're (finally) bringing full hwloc services up in Open MPI.
>
> One of the things we want to do is send server topologies from back-end compute nodes to the front-end node. The XML export/import functionality would work for this, but a) it's a bit heavyweight, and b) it seems weird to require XML to build MPI.
>
> Is there any chance that a lighter-weight, simple string parsing module could be added to hwloc? I'm guessing that we could save a modest amount of string space (SWAG: 20%?), but we wouldn't need a dependency on libxml, which would be good.
>
> I took a lstopo --no-io foo.xml output on an older xeon machine and, while sitting on a boring teleconf, I manually converted it in emacs to a (slightly) simpler text format. I attached the two files. There's a modest space savings (about 17%). But libxml clearly would not be necessary.
>
> Do you think this would be easy to implement?
>
what do you think about json?
i think is a lot better than xml ... and really easy to parse

cheers
>
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- --
Degree Alaniz Marcelo
Frontend Development
HPC PhD Student
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