I really like Open-MPI and its Modular Component Architecture.
The --mca parameters are so useful for learning and testing things !
So here are my questions.
I know that the default point-to-point messaging layer is ob1
Obi-Wan Kenobi PML). I know that there is also the PML
cm (the Connor MacLeod PML).
From what I understand, the force is strong with Obi-Wan Kenobi, so
can use various byte transfer layers (BTLs).
And there can be only one highlander (probably Connor MacLeod) so
when I use the MTL psm, I can not use any of the BTLs because Connor
MacLeod can only be alone at the end.
But what about the PML csum ?
What exactly is the PML csum (checksum) doing ?
Which code is the PML csum using for actually transferring stuff
MPI ranks ? BTLs or MTLs or something else or nothing ?
I have searched the web a little but have not found much about it.
If I use the MTL psm, can the PML csum be used to detect message
corruption ? I guess the answer is no because csum is not Connor
I have read that when the MTL psm is used, all the Open-MPI BTL
What code would the PML dr use to move bytes around should it
be stable and production-ready ?
And my final question:
When a company design a new interconnect, why choose the MTL
(and thus the PML cm) instead of the BTL architecture (with the ob1
It seems to me that ob1 and BTLs are mature and that BTLs self and
sm are quite
useful and bug-free for what I know. New code should only do the
case when the two
MPI processes are on different nodes, right ?
Thank you !
p.s.: I found the silly names here ->