UPC Teams

• Previous message: James Dinan: "Re: Overlapping put/get events"

Hi,

Does anyone know whether the proposed UPC teams/thread groups extensions 
are available in Berkeley UPC?

Also, I had a thought wrt how to use groups to enhance locality.  I'm 
not sure if this has already been suggested, but here goes:

The proposed extension contains a UPC_TEAM_ALL that contains all 
threads.  I was thinking the runtime system could also provide something 
like UPC_TEAM_LOCAL that allows the programmer to determine which UPC 
threads are on the local SMP node in a cluster (this might need to be 
more general to handle a variety of architectures but hear me out).

In order to make better/frequent use of this, we might want more 
convenient wrappers to map between a team and UPC_TEAM_ALL:

int upc_team_global_id(upc_team_t *team, int local_id) {
   int trans_id;
   upc_group_translate_threads(upc_group_from_team(team),
     upc_group_from_threads(UPC_TEAM_ALL), &local_id, &trans_id, 1);
   return trans_id;
}

This would be a non-collective call that maps the local id of a team 
member to their thread id in UPC_TEAM_ALL.

int upc_team_local_id(upc_team_t *team, int global_id);

This is also non-collective and tells us the local id of thread 
global_id within the team.  If the thread is not in the team we get 
UPC_THREAD_UNDEFINED.

Using this we could write something like:

int upc_islocal(shared void *ptr) {
   if (upc_team_local_id(UPC_TEAM_LOCAL, upc_threadof(ptr)) !=
       UPC_THREAD_UNDEFINED)
     return 1;
   else
     return 0;
}

One quick example of where we could use upc_islocal(), would be to 
determine when element-wise access is ok and when we should do a bulk 
transfer via upc_memget().

Regards,
  ~Jim.

• Previous message: James Dinan: "Re: Overlapping put/get events"