How does Open MPI use shared memory for communication between two processes
on the same host meaning who creates the shared memory?
Both the processes running on the host have their own private buffers. So
buf1 sent by Process 1 should reach buf2 of Process 2. How is this handled?
Is it that buf
Hi,
On 11/8/06, Greg Lindahl wrote:
On Tue, Nov 07, 2006 at 05:02:54PM +, Miguel Figueiredo Mascarenhas Sousa
Filipe wrote:
> if your aplication is on one given node, sharing data is better than
> copying data.
Unless sharing data repeatedly leads you to false sharing and a loss
in perfo
On 11/8/06, Miguel Figueiredo Mascarenhas Sousa Filipe
wrote:
Hi,
On 11/8/06, Greg Lindahl wrote:
> On Tue, Nov 07, 2006 at 05:02:54PM +, Miguel Figueiredo Mascarenhas Sousa
Filipe wrote:
>
> > if your aplication is on one given node, sharing data is better than
> > copying data.
>
> Unle
Miguel Figueiredo Mascarenhas Sousa Filipe wrote:
> H
>>> the MPI model assumes you don't have a "shared memory" system..
>>> therefore it is "message passing" oriented, and not designed to
>>> perform optimally on shared memory systems (like SMPs, or numa-CCs).
>>>
>> For many programs with
On Wed, 8 Nov 2006, Larry Stewart wrote:
Miguel Figueiredo Mascarenhas Sousa Filipe wrote:
H
the MPI model assumes you don't have a "shared memory" system..
therefore it is "message passing" oriented, and not designed to
perform optimally on shared memory systems (like SMPs, or numa-CCs).
For
i've run my mm5 weather modeling app over mpich gig-e
& myrinet, & open-mpi gig-e. when i tried open-mpi
over myrinet, i was able to compile & run w/o issue,
but i get no net traffic over the myrinet switch. the
job cranks up the cpu's but never completes. i'm
using the myrinet MX driver. i hav
On Nov 8, 2006, at 8:06 AM, shane kennedy wrote:
i've run my mm5 weather modeling app over mpich gig-e
& myrinet, & open-mpi gig-e. when i tried open-mpi
over myrinet, i was able to compile & run w/o issue,
but i get no net traffic over the myrinet switch. the
job cranks up the cpu's but never
Hello everyone,
I am having a hard time getting OpenMPI (1.1.2) to run in a
heterogeneous environment. In short, here is my command line:
orterun --prefix ~/openmpi_x86_64/ -hostfile head -np 2 mandelbrot-mpi_x86_64
1 400 400 0 : --prefix ~/openmpi_i686/ -hostfile nodes -np `wc -l
> > i've run my mm5 weather modeling app over mpich
> gig-e
> > & myrinet, & open-mpi gig-e. when i tried
> open-mpi
> > over myrinet, i was able to compile & run w/o
> issue,
> > but i get no net traffic over the myrinet switch.
> the
> > job cranks up the cpu's but never completes. i'm
> > usi
On Wed, Nov 08, 2006 at 09:57:18AM -0500, Hugh Merz wrote:
> The conventional wisdom of pure MPI being as good as hybrid models
> is primarily driven by the fact that people haven't had much incentive
> to re-write their algorithms to support both models.
Actually, I was thinking of apps where pe
On Wed, Nov 08, 2006 at 12:25:20PM +, Miguel Figueiredo Mascarenhas Sousa
Filipe wrote:
> > Unless sharing data repeatedly leads you to false sharing and a loss
> > in performance.
>
> what does that mean.. I did not understand that.
Google indexes a bunch of good webpages on "false sharing
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