https://svn.open-mpi.org/trac/ompi/wiki/ProcessPlacement
The wiki page is incomplete at the moment, but I hope to complete it over the next few days. I will provide updates on the devel list. As the wiki page states, the default and most commonly used options remain unchanged (except as noted below). New, esoteric and complex options have been added, but unless you are a true masochist, you are unlikely to use many of them beyond perhaps an initial curiosity-motivated experimentation.
In a nutshell, this commit revamps the map/rank/bind procedure to take into account topology info on the compute nodes. I have, for the most part, preserved the default behaviors, with three notable exceptions:
1. I have at long last bowed my head in submission to the system admin's of managed clusters. For years, they have complained about our default of allowing users to oversubscribe nodes - i.e., to run more processes on a node than allocated slots. Accordingly, I have modified the default behavior: if you are running off of hostfile/dash-host allocated nodes, then the default is to allow oversubscription. If you are running off of RM-allocated nodes, then the default is to NOT allow oversubscription. Flags to override these behaviors are provided, so this only affects the default behavior.
2. both cpus/rank and stride have been removed. The latter was demanded by those who didn't understand the purpose behind it - and I agreed as the users who requested it are no longer using it. The former was removed temporarily pending implementation.
3. vm launch is now the sole method for starting OMPI. It was just too darned hard to maintain multiple launch procedures - maybe someday, provided someone can demonstrate a reason to do so.
As Jeff stated, it is impossible to fully test a change of this size. I have tested it on Linux and Mac, covering all the default and simple options, singletons, and comm_spawn. That said, I'm sure others will find problems, so I'll be watching MTT results until this stabilizes.
This commit was SVN r25476.
1. no -np provided - put one proc/node across all allocated nodes
2. -np N provided, N > #nodes - we print a pretty error message and exit
3. -np N provided, N <= #nodes - put one proc/node across N nodes
I also added a new orte constant (ORTE_ERR_SILENT) that allows us to pass up the chain that an error was encountered, but NOT print ORTE_ERROR_LOG messages. This is intended to be used for cases where the error we encounter is NOT an orte error, but rather is one associated with incorrect user input (e.g., the preceding case 2). In such cases, there is no point in printing an ORTE_ERROR_LOG chain of messages as it isn't an orte error.
This commit was SVN r12821.
Update the help text to report errors when not following that rule.
Also updated the RMAPS help text to reflect the reorganization of some of the round-robin code into the base.
The new functionality has been tested under Mac OS-X and on Odin using an MPI program. Both byslot and bynode mapping have been checked and verified. Operational support for other systems needs to be verified - I respectfully request people's help in doing so.
This commit was SVN r10708.
command:
svn merge -r 7567:7663 https://svn.open-mpi.org/svn/ompi/tmp/jjhursey-rmaps .
(where "." is a trunk checkout)
The logs from this branch are much more descriptive than I will put
here (including a *really* long description from last night). Here's
the short version:
- fixed some broken implementations in ras and rmaps
- "orterun --host ..." now works and has clearly defined semantics
(this was the impetus for the branch and all these fixes -- LANL had
a requirement for --host to work for 1.0)
- there is still a little bit of cleanup left to do post-1.0 (we got
correct functionality for 1.0 -- we did not fix bad implementations
that still "work")
- rds/hostfile and ras/hostfile handshaking
- singleton node segment assignments in stage1
- remove the default hostfile (no need for it anymore with the
localhost ras component)
- clean up pls components to avoid duplicate ras mapping queries
- [possible] -bynode/-byslot being specific to a single app context
This commit was SVN r7664.
