On Thu, 17 Jul 2003, Matthew Bettencourt wrote:
> lam-7.0 issues
> WHen I unpack the latest version and run configure I get
>
> checking size of FORTRAN INTEGER... unknown
> configure: WARNING: *** Problem running configure test!
> [snipped]
>
> I looked back about 100 lines and saw nothing I understood? has anyone
> built this for aix 5.1??
Yes. I can build properly on AIX 5.1 with the native AIX compilers
(xlc/xlc_r, xlC/xlC_r, xlf/xlf_r). I have not tested the GNU compilers on
AIX 5.1 because our AIX 5.1 machine doesn't have them installed. :-)
Generally, this error indicates that configure was not able to compile/run
a simple fortran program. Can you verify that your fortran compiler
works?
> Performance issue. On these SP systems I am noticing a latency of a
> MPI_Send/Recv of about 1.2 to 1.5ms. Is this typical. With the native
> MPI I am getting someing like .3ms or a factor of 4 better. I am trying
> using the IBM's Colony switch for communication (binding to that IP vs
> the ethernet IP on lamboot)
Yes, I would expect this kind of behavior from LAM on IBM hardware. Keep
in mind that IBM's MPI is implemented on LAPI (and probably shared memory
-- I'm not too familiar with IBM's MPI), and LAM will either use shared
memory or TCP. LAM's shared memory RPI *may* get close results to IBM's
MPI, but I suspect that IBM has tweaked the heck out of their MPI to get
absolutely fantastic performance on their hardware. That, and the fact
that native LAPI performance is significantly better than native TCP
performance pretty much guarantees that IBM's MPI will outperform LAM on
their hardware.
It is not outside the realm of possibility that LAM will have a LAPI RPI
to get performance in the same order of magnitude as IBM's MPI, but we
don't have the resources to do that at the present time.
Anyone want to volunteer? :-)
--
{+} Jeff Squyres
{+} jsquyres_at_[hidden]
{+} http://www.lam-mpi.org/
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