[ROOT] Re: CINT cpu speed?

From: Rene Brun (Rene.Brun@cern.ch)
Date: Tue Jan 28 2003 - 14:57:02 MET


Art,

I do not understand this factor 10. Are you sure than you run
with the same CINT optimisation level in both cases?
Could you send me your file pion-1.612.tuples?

Rene Brun

"Arthur E. Snyder" wrote:
> 
> I find speed of C++ interpreter to be much slower in new versions of root
> than in old ones. Using the code attached below to read in an ASCII file I
> find a factor of 2 decrease in the speed of the macro between 3.02-07
> and  2.23-12. Why is that? This not progress!
> 
> Even stranger is that the original version of this code which used "cout"
> rather than "printf" to print out variable "count" is even slower. That
> one ran 10x slower in 3.02-07 than 2.23-12 the 1st time it was executed,
> but improved to only 2x slower when executed again. I'm not sure if this
> really had anything to do with use of "cout <<" instead of  printf, since
> other minor changes such as putting in a few statements to print cpu time
> used also produced improvement from 10x worse to only 2x worse.
> 
> Anybody have any idea what's going on here?
> 
> -Art Snyder, SLAC
> 
> ASCII tuple reader:
> 
> TNtuple* readASCII() {
> ifstream fp("paw/pion-1.612.tuples");
> 
> TNtuple* temp=new TNtuple("ntuple","ascii
> data","evtno:npievt:status:idmom:eve:ideve:b:idb:xb:yb:zb:
> xeve:yeve:zeve:pxpimc:pypimc:pzpimc:ptpimc:ppimc:thpimc:
> phipimc:pxpirc:pypirc:pzpirc:ptpirc:ppirc:thpirc:phipirc:
> xpirc:ypirc:zpirc:nsvtpi:ndchpi:lenpi:delth:delthalt:pxalt:
> pyalt:pzalt:thalt:phialt:xalt:yalt:zalt:pxmom:pymom:pzmom:
> ptmom:pmom:thmom:phimom:xmom:ymom:zmom:idpimom:idpigma");
> 
> Float_t array[56];
> Int_t loop=1;
> Int_t count=0;
> 
> while(loop) {
>  for(Int_t i=0; i<56; i++) {
> fp >> array[i];
>  }
> temp->Fill(array);
> count++;
> if(count>=16434) break;
> if(count%1000==1) printf("count: %d \n",count);
> }
> 
> printf("total: %d \n ",count);
> return temp;
> }
> 
> A.E. Snyder, Group EC                        \!c*p?/
> SLAC Mail Stop #95                          ((.   .))
> Box 4349                                        |
> Stanford, Ca, USA, 94309                      '\|/`
> e-mail:snyder@slac.stanford.edu                 o
> phone:650-926-2701                              _
> http://www.slac.stanford.edu/~snyder          BaBar
> FAX:650-926-2657                          Collaboration



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