Takahiro, Thanks for the patch. I deplore the lost of the hash table in the attribute management, as the potential of transforming all attributes operation to a linear complexity is not very appealing.
As you already took the decision C, it means that at the communicator destruction stage the hash table is not relevant anymore. Thus, I would have converted the hash table to an ordered list (ordered by the creation index, a global entity atomically updated every time an attribute is created), and proceed to destroy the attributed in the desired order. Thus instead of having a linear operation for every operation on attributes, we only have a single linear operation per communicator (and this during the destruction stage). George. On Jan 16, 2013, at 16:37 , KAWASHIMA Takahiro <rivis.kawash...@nifty.com> wrote: > Hi, > > I've implemented ticket #3123 "MPI-2.2: Ordering of attribution deletion > callbacks on MPI_COMM_SELF". > > https://svn.open-mpi.org/trac/ompi/ticket/3123 > > As this ticket says, attributes had been stored in unordered hash. > So I've replaced opal_hash_table_t with opal_list_t and made necessary > modifications for it. And I've also fixed some multi-threaded concurrent > (get|set|delete)_attr call issues. > > By this modification, following behavior changes are introduced. > > (A) MPI_(Comm|Type|Win)_(get|set|delete)_attr function may be slower > for MPI objects that has many attributes attached. > (B) When the user-defined delete callback function is called, the > attribute is already removed from the list. In other words, > if MPI_(Comm|Type|Win)_get_attr is called by the user-defined > delete callback function for the same attribute key, it returns > flag = false. > (C) Even if the user-defined delete callback function returns non- > MPI_SUCCESS value, the attribute is not reverted to the list. > > (A) is due to a sequential list search instead of a hash. See find_value > function for its implementation. > (B) and (C) are due to an atomic deletion of the attribute to allow > multi-threaded concurrent (get|set|delete)_attr call in MPI_THREAD_MULTIPLE. > See ompi_attr_delete function for its implementation. I think this does > not matter because MPI standard doesn't specify behavior in such cases. > > The patch for Open MPI trunk is attached. If you like it, take in > this patch. > > Though I'm a employee of a company, this is my independent and private > work at my home. No intellectual property from my company. If needed, > I'll sign to Individual Contributor License Agreement. > > Regards, > KAWASHIMA Takahiro > <delete-attr-order.patch.gz>_______________________________________________ > devel mailing list > de...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/devel
