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Subject: Re: [OMPI devel] Problem w/ documented SPARC/gcc flags (1.5rc5 and 1.4.3rc1)
From: Paul H. Hargrove (PHHargrove_at_[hidden])
Date: 2010-08-25 18:32:38


Trying Rolf's suggestion, I configure 1.4.3rc1 with
   CFLAGS="-mv8plus -Wa,-xarch=v8plus" CXXFLAGS="-mv8plus
-Wa,-xarch=v8plus"
I find that I get configure past the v8+/v9 Assembler ABI probe (but
didn't wait for the full configure to run).

Another datapoint in favor of #2 is that I can successfully build
1.4.3rc1 w/ gcc-4.3.3 when I configure with
    CC=gcc-4.3.3 CXX=g++-4.3.3 CFLAGS=-mv8plus CXXFLAGS=-mv8plus
And have configured (again stopping after the Assembler ABI probe) with
gcc-4.3.3 AND Rolf's flags
    CC=gcc-4.3.3 CXX=g++-4.3.3 CFLAGS=-mv8plus CC=gcc-4.3.3
CXX=g++-4.3.3 CFLAGS=-mv8plus

So, here is MY summary:

+ For gcc-4.3.3 README is providing correct information
+ For gcc-3.3.2 README is providing INcorrect information
+ For both gcc versions configure provides correct info on failure, but
following it prevents using the V8+ ABI.

My suggestion fix:

+ Edit README and configure both to suggest "-mv8plus -Wa,-xarch=v8plus"
as that should be correct for either compiler version.

-Paul

Rolf vandeVaart wrote:
> Paul, is it possible for you to try one more thing. Can you
> reconfigure with
>
> CFLAGS="-mv8plus -Wa,-xarch=v8plus"
>
> I think this will get past the configure test as the configure test is
> compiling a piece
> of assembly, and for some reason, the -mv8plus is not finding its way
> to the assembler.
>
> If that works, then we eliminate #2 on your list below, and have to
> decide between
> #1 and #3.
> Rolf
>
> On 08/25/10 15:56, Paul H. Hargrove wrote:
>> In both 1.5rc5 and 1.4.3rc1, README says:
>> - Open MPI does not support the Sparc v8 CPU target, which is the
>> default on Sun Solaris. The v8plus (32 bit) or v9 (64 bit)
>> targets must be used to build Open MPI on Solaris. This can be
>> done by including a flag in CFLAGS, CXXFLAGS, FFLAGS, and FCFLAGS,
>> -xarch=v8plus for the Sun compilers, -mv8plus for GCC.
>>
>> However, the -mv8plus flag DOES NOT work for me.
>> The following occurs for both 1.5rc5 and 1.4.3rc1:
>>
>> $ uname -a
>> SunOS lem.lbl.gov 5.10 s10_69 sun4u sparc SUNW,Ultra-5_10
>>
>> $ gcc --version
>> gcc (GCC) 3.3.2
>> Copyright (C) 2003 Free Software Foundation, Inc.
>> This is free software; see the source for copying conditions. There
>> is NO
>> warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR
>> PURPOSE.
>>
>> $ [path_to]/configure --disable-mpi-f77 --disable-mpi-f90
>> CFLAGS=-mv8plus CXXFLAGS=-mv8plus
>> [...]
>> *** Assembler
>> [...]
>> checking if have Sparc v8+/v9 support... no
>> configure: WARNING: Sparc v8 target is not supported in this release
>> of Open MPI.
>> configure: WARNING: You must specify the target architecture v8plus
>> configure: WARNING: (cc: -xarch=v8plus, gcc: -mcpu=v9) for CFLAGS,
>> CXXFLAGS,
>> configure: WARNING: FFLAGS, and FCFLAGS to compile Open MPI in 32 bit
>> mode on
>> configure: WARNING: Sparc processors
>> configure: error: Can not continue.
>>
>>
>> Following the recommendation from configure:
>> $ [path_to]/configure --disable-mpi-f77 --disable-mpi-f90
>> CFLAGS=-mcpu=v9 CXXFLAGS=-mcpu=v9
>> DOES work for both of the current RCs.
>>
>> So, I see a few possibilities:
>>
>> 1) -mv8plus SHOULD work (as -xarch=v8plus appears to w/ Suc C 5.10)
>> but configure is unconditionally too strict.
>> OR
>> 2) My gcc is older than other have tested and configure is mistakenly
>> thinking the ABI is wrong.
>> OR
>> 3) -mcpu=v9 is the proper incantation and README needs correction.
>>
>> No matter which of the above is correct, I suspect REAME and
>> configure need to give the user the same information.
>>
>> -Paul
>>
>> P.S. I can provide temporary machine access if needed to resolve this.
>> P.P.S. I am /still/ not finished testing all the platforms available
>> to me ;-)
>>
>
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-- 
Paul H. Hargrove                          PHHargrove_at_[hidden]
Future Technologies Group
HPC Research Department                   Tel: +1-510-495-2352
Lawrence Berkeley National Laboratory     Fax: +1-510-486-6900