Re: [ROOT] icc versus gcc ?

From: Fons Rademakers (Fons.Rademakers@cern.ch)
Date: Tue May 21 2002 - 17:36:24 MEST


I know gdb does not work good for g++. But the Intel compilers come with
the Intel ldb debugger (which is also supported via the ddd graphical
front-end). ldb has a gdb like command set.

Cheers, Fons.



On Tue, 2002-05-21 at 15:47, Victor Perevoztchikov wrote:
> Hi Fons,
> >   there remains one problem with the icc compiler in one CINT routine in
> what about icc debugger. The latest version gdb does not work at all for
> gcc.
> Is it the same for icc?
> 
> Victor
> 
> Victor M. Perevoztchikov   perev@bnl.gov
> Brookhaven National Laboratory MS 510A PO Box 5000 Upton NY 11973-5000
> tel office : 631-344-7894; fax 631-344-4206; home 631-345-2690
> 
> ----- Original Message -----
> From: "Fons Rademakers" <Fons.Rademakers@cern.ch>
> To: "Ahmet Sedat Ayan" <ayan@cms.physics.uiowa.edu>
> Cc: <roottalk@pcroot.cern.ch>
> Sent: Tuesday, May 21, 2002 4:26 AM
> Subject: Re: [ROOT] icc versus gcc ?
> 
> 
> > Hi Ahmet,
> >
> >   there remains one problem with the icc compiler in one CINT routine in
> > -O mode. This problem has been localized and reproduced in a small test
> > program and Intel is working on a fix. In the ROOT makefile I've added a
> > protection such that this file is always compiled in -O0 mode while the
> > rest of ROOT is compiled in -O (i.e. -O2) mode. I retract evrything I
> > said about icc in the April 8th mail, since a lot of confusion was based
> > on a misunderstanding of the icc man pages in relation to building
> > shared libs. I use icc as default compiler on my machine.
> >
> > Cheers, Fons.
> >
> >
> >
> > On Mon, 2002-05-20 at 22:47, Ahmet Sedat Ayan wrote:
> > >
> > > Dear Rooters,
> > >
> > > I have been investigating if I should be re-compiling/installing
> > > my ROOT with Intel's "icc". In the roottalk I think there are
> conflicting
> > > opinions on the performance and/or worthiness of this (see the messages
> > > below by Fonds)
> > >
> > > I have a Redhat7.2 Linux box with a P4 1.8 GHz processor and running my
> > > analysis code (no GUI etc involved); reading data from the disk (I/O) ,
> > > calculating same variables and filling and plotting many histograms.
> > > (Whole data run takes about 3-4 hours)
> > >
> > > My question is then if it is worth to compile ROOT  with "icc" and if I
> > > did if I would see a big improvement in the analysis code running time??
> > >
> > > thanks a lot
> > > ahmet
> > >
> > >
> > >
> > > ****************************************************************
> > > May,14,2002
> > > ROOTers,
> > >
> > >   with the current version of ROOT in CVS we now fully support the
> > > latest Intel icc v6 compiler. This compiler provides about 30 to 45%
> > > faster code then gcc 2.95 or gcc 3.x on Intel PIII and P4 systems. The
> > > Linux version of this compiler can be freely downloaded from:
> > > http://www.intel.com/software/products/eval/ (get the "non-commercial
> > > unsupported software" version which is free). With ROOT on my P4 machine
> > > this compiler produces 35% faster code (both in debug and optimized
> > > mode). At the same time it compiles also about 20-30% faster than gcc.
> > > To install ROOT do: ./configure linuxicc; make
> > >
> > > For more on this compiler see also:
> > > http://www.open-mag.com/features/Vol_15/IntelC/intelc.htm
> > >
> > > It is nice to see your good old PC suddenly run 35% faster.
> > >
> > >
> > >
> > > Cheers, Fons.
> > >
> ****************************************************************************
> > > On April,8th,2002
> > > Hi Andre,
> > >
> > >   your observations are correct. Concerning icc (and ecc, the IA-64
> > > version of icc), I have several incident reports open with Intel
> > > concerning the compiler failing on ROOT's very conservative C++ code.
> > > Actually the icc v6beta cannot even execute ROOT because it generates in
> > > all cases (-g, -O, etc) bad code. This Intel compiler has its origins as
> > > Intel's SPEC reference compiler, i.e. it has been optimized and tuned
> > > with the sole goal to produce the best binaries for the SPEC program
> > > suite (rumour has it it could even generate SPEC binaries without input
> > > source code, i.e. the binaries were hand coded and included in the
> > > compiler proper).
> > >
> > > Cheers, Fons.
> > >
> > > ----------------------------
> > >
> > > ***************
> > >
> > > Ahmet Sedat Ayan
> > >
> > > Physics & Astronomy Dept.
> > > Van Allen Hall
> > > University of Iowa
> > > Iowa City, IA, 52242
> > >
> > > Voice      : (++ 1 319) 335-1941 (W) (GMT-6)
> > > Occupation : Ph.D Candidate (But still dreamer!)
> > > e-mail     : ayan@cms.physics.uiowa.edu
> > > web        : http://jazz.physics.uiowa.edu/~ayan
> > >
> > --
> > Org:    CERN, European Laboratory for Particle Physics.
> > Mail:   1211 Geneve 23, Switzerland
> > E-Mail: Fons.Rademakers@cern.ch              Phone: +41 22 7679248
> > WWW:    http://root.cern.ch/~rdm/            Fax:   +41 22 7679480
> >
-- 
Org:    CERN, European Laboratory for Particle Physics.
Mail:   1211 Geneve 23, Switzerland
E-Mail: Fons.Rademakers@cern.ch              Phone: +41 22 7679248
WWW:    http://root.cern.ch/~rdm/            Fax:   +41 22 7679480



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