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From: Jeff Squyres (jsquyres_at_[hidden])
Date: 2007-08-27 22:04:49


On Aug 27, 2007, at 2:50 PM, Greg Watson wrote:

> Until now I haven't had to worry about the opal/orte thread model.
> However, there are now people who would like to use ompi that has
> been configured with --with-threads=posix and --with-enable-mpi-
> threads. Can someone give me some pointers as to what I need to do in
> order to make sure I don't violate any threading model?

Note that this is *NOT* well tested. There is work going on right
now to make the OMPI layer be able to support MPI_THREAD_MULTIPLE
(support was designed in from the beginning, but we haven't ever done
any kind of comprehensive testing/stressing of multi-thread support
such that it is pretty much guaranteed not to work), but it is
occurring on the trunk (i.e., what will eventually become v1.3) --
not the v1.2 branch.

> The interfaces I'm calling are:
>
> opal_event_loop()

Brian or George will have to answer about that one...

> opal_path_findv()

This guy should be multi-thread safe (disclaimer: haven't tested it
myself); it doesn't rely on any global state.

> orte_init()
> orte_ns.create_process_name()
> orte_iof.iof_subscribe()
> orte_iof.iof_unsubscribe()
> orte_schema.get_job_segment_name()
> orte_gpr.get()
> orte_dss.get()
> orte_rml.send_buffer()
> orte_rmgr.spawn_job()
> orte_pls.terminate_job()
> orte_rds.query()
> orte_smr.job_stage_gate_subscribe()
> orte_rmgr.get_vpid_range()

Note that all of ORTE is *NOT* thread safe, nor is it planned to be
(it just seemed way more trouble than it was worth). You need to
serialize access to it.

-- 
Jeff Squyres
Cisco Systems