Thanks, Paul. That was useful! although in my case it was enough to
allocate my own arrays using posix_memalign. The internals of OpenMPI
did not play any role, which I guess is quite natural assuming OpenMPI
doesn't reallocate.
But since that worked, it means that 1.10.6 deals somehow better with
unaligned data. Anyone knows the reason for this?
Marcin
On 05/04/2017 04:29 PM, Paul Kapinos wrote:
Note that 2.x lost the memory hooks, cf. the thread
https://www.mail-archive.com/devel@lists.open-mpi.org/msg00039.html
The numbers you have looks like 20% loss we also have seen with 4.x
vs. 1.10.x versions. Try the dirty hook with 'memalign', LD_PRELOAD this:
$ cat alignmalloc64.c
/* Dirk Schmidl (ds53448b), 01/2012 */
#include <malloc.h>
void* malloc(size_t size){
return memalign(64,size);
}
$ gcc -c -fPIC alignmalloc64.c
$ gcc -shared -Wl,-soname,$(LIBNAME64) -o $(LIBNAME64) alignmalloc64.o
On 05/04/17 12:27, marcin.krotkiewski wrote:
The resultsare puzzling: it seems that something changed starting
from version
2.x, and the FDR system performs much worse than with the prior
1.10.x release.
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