OpenMPI Users,
I am using AMD processocers with CMT, where two cores constitute a
module, and there is only one FPU per module, so each pair of cores has
to share a single FPU. I want to use only one core per module so there
is no contention between cores in the same module for the single FPU
Gilles Gouaillardet writes:
> Dave,
>
> the builtin memchecker can detect MPI usage errors such as modifying
> the buffer passed to MPI_Isend() before the request completes
OK, thanks. The implementation looks rather different, and it's not
clear without checking the code in detail how it diffe
Christoph Niethammer writes:
> Hi Dave,
>
> The memchecker interface is an addition which allows other tools to be
> used as well.
Do you mean it allows other things to be hooked in other than through
PMPI?
> A more recent one is memPin [1].
Thanks, but Pin is proprietary, so it's no use as an
Gilles,
Thanks for your swift response. On this system, /dev/shm only has 256M
available so that is no option unfortunately. I tried disabling both
vader and sm btl via `--mca btl ^vader,sm` but Open MPI still seems to
allocate the shmem backing file under /tmp. From my point of view,
missing
Dave,
the builtin memchecker can detect MPI usage errors such as modifying
the buffer passed to MPI_Isend() before the request completes
all the extra work is protected
if ( running_under_valgrind() ) {
extra_checks();
}
so if you are not running under valgrind, the overhead should be unnotic
Joseph,
the error message suggests that allocating memory with
MPI_Win_allocate[_shared] is done by creating a file and then mmap'ing
it.
how much space do you have in /dev/shm ? (this is a tmpfs e.g. a RAM
file system)
there is likely quite some space here, so as a workaround, i suggest
you use t
All,
I have been experimenting with large window allocations recently and
have made some interesting observations that I would like to share.
The system under test:
- Linux cluster equipped with IB,
- Open MPI 2.1.1,
- 128GB main memory per node
- 6GB /tmp filesystem per node
My obser
Hi Dave,
The memchecker interface is an addition which allows other tools to be used as
well.
A more recent one is memPin [1].
As stated in the cited paper, the overhead is minimal when not attached to a
tool.
>From my experience a program running under pin tool control runs much faster
>than
Apropos configuration parameters for packaging:
Is there a significant benefit to configuring built-in memchecker
support, rather than using the valgrind preload library? I doubt being
able to use another PMPI tool directly at the same time counts.
Also, are there measurements of the performance
