As suspected, it was a component adding the -lpthread. The problem
is that the component in question is ROMIO and it does it because it
thinks that -lpthread is needed to make asynchronous I/O work
properly. Which is actually a possibility, depending on which
version of the Linux kernel you are using.
If you need asynchronous MPI-2 IO functions, I think you have to live
with the dependency on -lpthread. However, if you don't need MPI-2
IO functionality at all, you can configure Open MPI with --disable-io-
romio or if you can live without aio support for ROMIO, you can
configure Open MPI with --with-io-romio-flags='--disable-aio'.
I believe that disabling aio support in ROMIO will remove the pthread
dependency.
Brian
On Mar 17, 2006, at 10:57 AM, Greg Watson wrote:
$ mpicc -showme
gcc -I/usr/local/include -I/usr/local/include/openmpi -I/usr/local/
include/openmpi/opal -I/usr/local/include/openmpi/orte -I/usr/local/
include/openmpi/ompi -L/usr/local/lib -lmpi -lorte -lopal -lutil -
lnsl -ldl -lbproc -lbproc -lbproc -lbproc -lbproc -lbproc -lpthread -
lrt -Wl,--export-dynamic -lm -lutil -lnsl -ldl
Looks like -lpthread is there...
Thanks,
Greg
On Mar 17, 2006, at 8:33 AM, Brian Barrett wrote:
On Mar 17, 2006, at 10:17 AM, Greg Watson wrote:
I'm building OMPI 1.0.2a9 on a bproc machine (Yellow Dog Linux 4.0/
ppc). It just has an ethernet interface, no fancy network.
I've tried configuring as follows:
./configure --enable-static --disable-shared --without-threads --
with-
devel-headers
and
./configure --enable-static --disable-shared --without-threads --
without-mpi-threads --with-devel-headers
The second one should be --disable-mpi-threads, but it really doesn't
matter - specifying --without-threads will automatically disable mpi
threads. So these are both correct for what you are trying to do.
Clearly, however, something else is going on :/.
In both cases, I'm still seeing the thread library linked in the
final executable:
$ mpicc -o testmpi testmpi.c
$ ldd testmpi
libutil.so.1 => /lib/libutil.so.1 (0x0f590000)
libnsl.so.1 => /lib/libnsl.so.1 (0x0e850000)
libdl.so.2 => /lib/libdl.so.2 (0x0fdc0000)
libbproc.so.4 => /usr/lib/libbproc.so.4 (0x0fe50000)
libpthread.so.0 => /lib/tls/libpthread.so.0 (0x0fc40000)
librt.so.1 => /lib/tls/librt.so.1 (0x0f660000)
libm.so.6 => /lib/tls/libm.so.6 (0x30013000)
libc.so.6 => /lib/tls/libc.so.6 (0x0fe70000)
/lib/ld.so.1 => /lib/ld.so.1 (0x0ffd0000)
$
What does "mpicc -showme" show? If it includes something like -
pthread or -lpthread, can you send the config.log file from Open MPI?
Since ldd doesn't list the OMPI libraries as dependencies, it's a
pretty good assumption that they were statically linked in (so at
least the --disable-shared part worked). Therefore, if mpicc doesn't
explicitly list -pthread or -lpthread, then the dependency is coming
from one of two places. Either the compiler is explicitly adding -
lpthread anyway (unlikely) or one of the other libraries that we
added a -l for does depend on pthreads for some reason. I can't
think off hand what we might add to cause this, so it might mean
searching through the list of libraries with ldd to see if one of
them includes a dependency on /lib/tls/libpthread.so.
Checking ompi_config.h shows:
#define HAVE_PTHREAD_H 1
#define OMPI_ENABLE_MPI_THREADS 0
#define OMPI_ENABLE_PROGRESS_THREADS 0
#define OMPI_HAVE_POSIX_THREADS 0
#define OMPI_HAVE_SOLARIS_THREADS 0
#define OMPI_THREADS_HAVE_DIFFERENT_PIDS 0
If anyone can tell me what I'm doing wrong, it would be appreciated.
I need to get this working for a demo on Monday.
That looks like Open MPI's configure script disabled threads
support. The HAVE_PTHREAD_H should not be used to figure out if we
should use pthread support or not - it's only given to indicate
whether pthread.h exists as a useable header file.
Brian
--
Brian Barrett
Open MPI developer
http://www.open-mpi.org/
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