se the temporary file for shared memory
> management (though I have not figured out the mechanism yet) and achieves a
> better performance (minor but noticable) with respect to openmpi.
>
> Any thoughts?
>
> Regards,
> Mahmood
>
> From: Jeff Squyres
> To: Open MPI
Sent: Monday, October 29, 2012 4:31 PM
Subject: Re: [OMPI users] openmpi shared memory feature
On Oct 29, 2012, at 11:01 AM, Ralph Castain wrote:
> Wow, that would make no sense at all. If P1 and P2 are on the same node, then
> we will use shared memory to do the transfer, as Jeff describ
On Oct 29, 2012, at 11:01 AM, Ralph Castain wrote:
> Wow, that would make no sense at all. If P1 and P2 are on the same node, then
> we will use shared memory to do the transfer, as Jeff described. However, if
> you disable shared memory, as you indicated you were doing on a previous
> message
lesystem
> anymore. Instead, they go directly to the shared memory (which is kinda the
> point).
>
> There are some corner cases where the contents of the shared memory can be
> written out to the filesystem (which, in the case of the network filesystem,
> would result in
P2 can communicate through the memory on 'B' which is fine. But I think there
should be more documentation on that.
Regards,
Mahmood
____________
From: Jeff Squyres
To: Mahmood Naderan ; Open MPI Users
Sent: Monday, October 29, 2012 1:28 PM
Subject:
ct 27, 2012, at 2:17 PM, Mahmood Naderan wrote:
> Thanks all. It is now cleared.
>
> Regards,
> Mahmood
>
> From: Damien
> To: Open MPI Users
> Sent: Saturday, October 27, 2012 7:25 PM
> Subject: Re: [OMPI users] openmpi shared memory feature
>
> Mahmood
Thanks all. It is now cleared.
Regards,
Mahmood
From: Damien
To: Open MPI Users
Sent: Saturday, October 27, 2012 7:25 PM
Subject: Re: [OMPI users] openmpi shared memory feature
Mahmood,
To build on what Jeff said, here's a short summary of how dis
Mahmood,
To build on what Jeff said, here's a short summary of how diskless
clusters work:
A diskless node gets its operating system through a physical network
(say gig-E), including the HPC applications and the MPI runtimes, from a
master server. That master server isn't the MPI head node,
On Oct 27, 2012, at 12:47 PM, Mahmood Naderan wrote:
> >Because communicating through shared memory when sending messages between
> >processes on the same server is far faster than going through a network
> >stack.
>
> I see... But that is not good for diskless clusters. Am I right? assume
>
communication go though network (from computing node to server) then IO and
> then network again (from server to computing node).
>
> Regards,
> Mahmood
>
> From: Jeff Squyres
> To: Mahmood Naderan ; Open MPI Users
>
> Sent: Saturday, October 27, 2012 6:19 PM
> Subject:
Re: [OMPI users] openmpi shared memory feature
On Oct 27, 2012, at 10:49 AM, Mahmood Naderan wrote:
> Why openmpi uses shared memory model?
Because communicating through shared memory when sending messages between
processes on the same server is far faster than going through a network stack.
On Oct 27, 2012, at 10:49 AM, Mahmood Naderan wrote:
> Why openmpi uses shared memory model?
Because communicating through shared memory when sending messages between
processes on the same server is far faster than going through a network stack.
> this can be disabled though by setting "--mca ^
Dear all,
Why openmpi uses shared memory model? this can be disabled though by setting
"--mca ^sm".
It seems that by default openmpi uses such feature (shared memory backing
files) which is strange.
Regards,
Mahmood
13 matches
Mail list logo
