Re: [ROOT] hsimple speed root_v3.04.02 vs root_v3.05.0x on LinuxRH7.1-3

From: Rene Brun (Rene.Brun@cern.ch)
Date: Fri May 09 2003 - 10:24:49 MEST


Hi Andrzej,

My strong advice is to move to gcc3.2. gcc2.96 is a very buggy compiler.
gcc3.2 has also some performance improvements (say 10 to 20%).

Rene Brun

Andrzej Kupsc wrote:
> 
> Thank you for the answer. We haven't found explanation for decreased
> performance of compiled $ROOTSYS/test/hsimple.cxx. One other thing
> which we would like to try is to use g++ 3.2 compiler.
> Maybe somebody has experience if one can expect big
> performance difference between code compiled with gcc 2.96 (RH 7.1-7.3 standard)
> and gcc 3.2?
> 
> Andrzej Kupsc
> 
> 
> 
> On Fri, 9 May 2003, Rene Brun wrote:
> 
> > Hi Andrzej,
> >
> > I cannot reproduce this problem with $ROOTSYS/test/hsimple.cxx.
> >
> > The main difference between 3.04 and 3.05 is the introduction by default
> > of the True Type Fonts. If you run the benchmarks.C with 3.04 without
> > using TTF and 3.05 with TTF, you may see a factor 2 on graphics
> > applications. If you use the new 3.05/05, you can disable TTF in system.rootrc.
> > We will work on the speed improvements with TTF.
> >
> > Rene Brun
> >
> > Andrzej Kupsc wrote:
> > >
> > > Hej,
> > >
> > >   We have found that some of our root based applications seems to run
> > > 2-4 times slower with root_v3.05.04 as compared to root_v3.04.02.
> > >
> > > In order to find the reason of decreased performance we have run standard
> > > root benchmarks with precompiled root versions as well as root_v3.05.04
> > > compiled from sources.
> > > The comparison was done on the same computers with the only difference
> > > being root version used. Most dramatic difference is with
> > > $ROOTSYS/test/hsimple.cxx which seems to be more than 4 times slower with
> > > ROOT 3.05/04.
> > > Does anyone observed similar decrease of performance with root_v3.05.04
> > > or have hints what could be wrong?
> > >
> > > Andrzej Kupsc
> > > ---------------------------------------------------------------
> > >                   The Svedberg Laboratory,
> > >                   Uppsala University, Uppsala.
> > > ---------------------------------------------------------------



This archive was generated by hypermail 2b29 : Thu Jan 01 2004 - 17:50:11 MET