Re: [ROOT] PROOF - loading shared libs

From: Fons Rademakers (
Date: Tue Aug 31 2004 - 09:32:29 MEST

Hi Thomas,

  sorry for the late reply. Concerning the loading of private shared
libraries you have to use the PROOF package manager, to build a little
PAR file (PROOF ARchive file) that contains either the source or
binaries of your private library and a script to compile it (if source)
and a script how to load it into the PROOF servers. An simple example
PAR build script and how to use it can be found in

PROOF jobs are in general I/O intensive, but a lot depends on how the
data is distributed over the cluster. Ideally if you have N nodes you
would distribute the data also over N nodes. In which case the PROOF
master will make sure that the workers will access, as much as possible,
the data locally. Also to make sure that the data that has to be
accessed over the network does not slow down the the processing too much
use preferably GB eth connections. Putting all data on a single node
will effectively serialize PROOF's operations (if the bandwidth of that
device is not very high).

We are working on a more concise PROOF manual in the coming months.

Cheers, Fons.

On Thu, 2004-08-26 at 11:27, Thomas Eberl wrote:
> Hi,
> I have setup a small PROOF cluster for testing.
> 4 PCs running Fedora Core 1, ROOT 400-08
> It seems to work, when I login and process a TNtuple which is accessed 
> from the nodes via rootd. I simply use TDSet.Draw();
> When I load my private shared libs containing my own data structure 
> definitions and try to process a TTree, it fails, as the slave nodes 
> don't know the classes. How can I tell them to load the shared libs as 
> well ?
> Is there some documentation on PROOF in the meanwhile (couldn't find it) 
> ? I'd be looking for an example that shows how to run a more complicated 
> script via PROOF. If the process is IO dominated, PROOF doesn't give a 
> speed benefit, it seems.
> Thanks
> Thomas
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