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From: Jeff Pummill (jpummil_at_[hidden])
Date: 2007-06-10 15:28:38


Perfect! Thanks Jeff!

The NAS Parallel Benchmark on a dual core AMD machine now returns this...
[jpummil_at_localhost bin]$ mpirun -np 1 cg.A.1
NAS Parallel Benchmarks 3.2 -- CG Benchmark
CG Benchmark Completed.
 Class = A
 Size = 14000
 Iterations = 15
 Time in seconds = 4.75
 Total processes = 1
 Compiled procs = 1
 Mop/s total = 315.32

...and...

[jpummil_at_localhost bin]$ mpirun -np 2 cg.A.2
NAS Parallel Benchmarks 3.2 -- CG Benchmark
 CG Benchmark Completed.
 Class = A
 Size = 14000
 Iterations = 15
 Time in seconds = 2.48
 Total processes = 2
 Compiled procs = 2
 Mop/s total = 604.46

Not quite linear, but one must account for all of the OS traffic that
one core or the other must deal with.

Jeff F. Pummill
Senior Linux Cluster Administrator
University of Arkansas
Fayetteville, Arkansas 72701
(479) 575 - 4590
http://hpc.uark.edu

"A supercomputer is a device for turning compute-bound
problems into I/O-bound problems." -Seymour Cray

Jeff Squyres wrote:
> Just remove the -L and -l arguments -- OMPI's "mpif90" (and other
> wrapper compilers) will do all that magic for you.
>
> Many -L/-l arguments in MPI application Makefiles are throwbacks to
> older versions of MPICH wrapper compilers that didn't always work
> properly. Those days are long gone; most (all?) MPI wrapper
> compilers do not need you to specify -L/-l these days.
>
>
>
> On Jun 10, 2007, at 3:08 PM, Jeff Pummill wrote:
>
>
>> Maybe the "dumb question" of the week, but here goes...
>>
>> I am trying to compile a piece of code (NPB) under OpenMPI and I am
>> having a problem with specifying the right library. Possibly
>> something I need to define in a LD_LIBRARY_PATH statement?
>>
>> Using Gnu mpich, the line looked like this...
>>
>> FMPI_LIB = -L/opt/mpich/gnu/lib/ -lmpich
>>
>> I tried to replace this with...
>>
>> FMPI_LIB = -L/usr/lib/openmpi/ -llibmpi
>>
>> to which the make responded...
>> mpif90 -O -o ../bin/cg.A.2 cg.o ../common/print_results.o ../common/
>> randdp.o ../common/timers.o -L/usr/lib/openmpi/ -llibmpi
>> /usr/bin/ld: cannot find -llibmpi
>> collect2: ld returned 1 exit status
>>
>> Wrong library file? Setup or path issue?
>>
>> --
>> Jeff F. Pummill
>> Senior Linux Cluster Administrator
>> University of Arkansas
>>
>> _______________________________________________
>> users mailing list
>> users_at_[hidden]
>> http://www.open-mpi.org/mailman/listinfo.cgi/users
>>
>
>
>