[ROOT] Re: CINT cpu speed?

From: Rene Brun (Rene.Brun@cern.ch)
Date: Tue Jan 28 2003 - 16:25:48 MET


Art,

I have run your script on your file
 - with CINT      : Real time 0:00:04, CP time 4.280
 - with ACLIC/gcc : Real time 0:00:04, CP time 3.590

As you can see, CINT is extremely fast and your factor 2 or 10!
must be somewhere else. Is your file somewhere on a slow server?

Rene Brun

"Arthur E. Snyder" wrote:
> 
> The factor of 10 is very odd. I'm just using standard root executables
> at SLAC. I haven't recompiled it our anything, so I assume they are
> optimized to the same level.
> 
> I'll send you the file.
> 
> ----- Original Message -----
> From: "Rene Brun" <Rene.Brun@cern.ch>
> To: "Arthur E. Snyder" <snyder@SLAC.Stanford.EDU>
> Cc: <roottalk@pcroot.cern.ch>
> Sent: Tuesday, January 28, 2003 5:57 AM
> Subject: Re: CINT cpu speed?
> 
> > 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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