Re: quation about automake with additional optimization

From: Hironori Ito (hito@rcf.rhic.bnl.gov)
Date: Thu Jul 24 2003 - 11:43:02 EDT

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    Ok. Thanks.

Hiro

Christian Holm Christensen wrote:

>Hi Hiro, 
>
>Hironori Ito <hito@rcf.rhic.bnl.gov> wrote concerning
>  Re: quation about automake with additional optimization [Thu, 24 Jul 2003 10:29:34 -0400] 
>----------------------------------------------------------------------
>  
>
>>Hello. 
>>
>>I knew CXXFLAGS option can be used, but this will replace any
>>default option in brat.  On the other hand, I just want to
>>_*append*_ my option (not replacing it).  For example, I can easily
>>add my option in ROOT by editing config/Makefile.linux.  Are there
>>any easy ways for BRAT/BRAG?
>>    
>>
>
>Yes, just do 
>
>     CXXFLAGS="-march=pentium4 -msse2 -O2 -g" ./configure 
>
>The "-O2 -g" is the only thing set per default by `./configure.'.  Iff
>we needed special flags for building BRAT, then we'd put that in the
>`AM_CXXFLAGS' variable in some `Makefile.am'.  
>
>For the record: the ROOT build system sucks!  I should know - I helped
>write some of the stuff.  Also, the best way to do custom stuff in the
>ROOT build, is to make the file `root/MyConf.mk' (I think), and define
>additional stuff there, say: 
>
>  #
>  CXXFLAGS	:= $(CXXFLAGS) -some-crazy-option
>
>  #
>  # EOF
>
>For the problem at hand, check if one of the optimisation levels
>`-O<x>' includes the stuff you need, and if so, pass `./configure' the
>option  `--enable-optimization=<x>'.  Also, you should really disable
>debugging symbols too `--disable-debug' if you care about speed (takes
>up memory).   
>
>Please note, that there was (and probably still is) a problem with
>optimisation on SMP machines and ROOT code and ROOT client code.  I
>believe the symptom is sporadic SIGSEGVs. 
>
>Hope that helps. 
>
>Yours, 
>
> ___  |  Christian Holm Christensen 
>  |_| |	 -------------------------------------------------------------
>    | |	 Address: Sankt Hansgade 23, 1. th.  Phone:  (+45) 35 35 96 91
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> ____|	 Email:   cholm@nbi.dk               Web:    www.nbi.dk/~cholm
> | |
>  
>

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