Re: info on proof

From: Fons Rademakers <>
Date: Thu, 26 May 2005 00:34:37 +0200

Hi Dani,

   how does you TT_cout.C script look like? You must make sure that in this case each slave is processing only one of the 8 files. To let each slave do something unique you have to use gProof->GetOrdinal() to indentify each slave.

Of course the most optimized use of PROOF you get with TSelector based analysis of a chain of files.

Cheers, Fons.

Daniel Cano wrote:
> Hi Fons
> I were more or less aware of this, but my situation is this. I have a
> multicpu machine and I want to make use of proof to be able to run on
> all the cpus at the same time and save time. For example my .C file
> (TT_cout.C) loads (chain.Add) a .root file. What I pretend is to load 8
> root files since the machine has 8 cpus and enough ram and disk speed to
> finish this 8 in the same time than a single file.
> What I do is
> root [0] gROOT->Proof("")
> password:
> PROOF set to parallel mode (8 slaves)
> (class TVirtualProof*)0x11a18790
> root [1] gProof->Exec(".x TT_cout.C")
> I already have the proof.conf file configured for this setup. I don't
> know if this is correct but I made some kind of comparison.
> If I start on this machine 8 root sessions and I use the TT_cout.C file
> that only loads one root file on each of the sessions, the 8 jobs are
> finished in about 40 minutes, more or less the same that if I only run
> one root session. But if I try in only one root session to use proof
> with the TT_cout.C that loads 8 root files, I have to stop it after more
> than four hours of 100% CPU comsumption, when I expected lets say not
> more than an hour.
> Well I don't know if I explained myself.
> Thanks in advance
> Dani
> On Mon, 2005-05-23 at 21:40 +0200, Fons Rademakers wrote:

>>Hi Daniel,
>>  you can execute any .C script on PROOF using:
>>note the script will be executed on all slaves or when in sequential mode 
>>(gProof->SetParallel(0)) on the master. You can use gProofServ->IsMaster() 
>>in the script to see if you run on a ROOT slave or on the master. In a 
>>local session gProofServ == 0.
>>Cheers, Fons.
>>Daniel Cano wrote:
>>>I suppose, that the .C scripts that run under ROOT, must be maked up, to
>>>run under PROOF. Are there any standard steps or guidelines to do so?
>>>Thanks in advance

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Received on Thu May 26 2005 - 00:36:11 MEST

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