[RFC] dash::copy: Implement global-to-global

Active team selection is now done by tag struct argument.

dash/include/dash/algorithm/Copy.h

@@ -624,25 +624,154 @@ copy_async(
 }
 #endif
 
+struct ActiveDestination{};
+struct ActiveSource{};
+
+/**
+ * Specialization of \c dash::copy as global-to-global blocking copy
+ * operation.
+ *
+ * \ingroup DashAlgorithms
+ */
+template <
+ class GlobInputIt,
+ class GlobOutputIt,
+ typename ValueType = typename GlobInputIt::value_type>
+GlobOutputIt copy(
+ GlobInputIt in_first,
+ GlobInputIt in_last,
+ GlobOutputIt out_first,
+ ActiveDestination /*unused*/)
+{
+ DASH_LOG_TRACE("dash::copy()", "blocking, global to global");
+
+ typedef typename GlobInputIt::size_type size_type;
+
+ size_type num_elem_total = dash::distance(in_first, in_last);
+ if (num_elem_total <= 0) {
+ DASH_LOG_TRACE("dash::copy", "input range empty");
+ return out_first;
+ }
+
+ auto g_out_first = out_first;
+ auto g_out_last = g_out_first + num_elem_total;
+
+ internal::ContiguousRangeSet<GlobOutputIt> range_set{g_out_first, g_out_last};
+
+ const auto & out_team = out_first.team();
+ out_team.barrier();
+
+ std::vector<dart_handle_t> handles;
+ internal::local_copy_chunks<ValueType> local_chunks;
+
+ size_type num_elem_processed = 0;
+
+ for (auto range : range_set) {
+
+ auto cur_out_first = range.first;
+ auto num_copy_elem = range.second;
+
+ DASH_ASSERT_GT(num_copy_elem, 0,
+ "Number of elements to copy is 0");
+
+ // handle local data only
+ if (cur_out_first.is_local()) {
+ auto dest_ptr = cur_out_first.local();
+ auto src_ptr = in_first + num_elem_processed;
+ internal::copy_impl(src_ptr,
+ src_ptr + num_copy_elem,
+ dest_ptr,
+ &handles,
+ local_chunks);
+ }
+ num_elem_processed += num_copy_elem;
+ }
+
+ internal::do_local_copies(local_chunks);
+
+ if (!handles.empty()) {
+ DASH_LOG_TRACE("dash::copy", "Waiting for remote transfers to complete,",
+ "num_handles: ", handles.size());
+ dart_waitall_local(handles.data(), handles.size());
+ }
+ out_team.barrier();
+
+ DASH_ASSERT_EQ(num_elem_processed, num_elem_total,
+ "Failed to find all contiguous subranges in range");
+
+ return g_out_last;
+}
+
 /**
  * Specialization of \c dash::copy as global-to-global blocking copy
  * operation.
  *
  * \ingroup DashAlgorithms
  */
-template <typename ValueType, class GlobInputIt, class GlobOutputIt>
+template <
+ class GlobInputIt,
+ class GlobOutputIt,
+ typename ValueType = typename GlobInputIt::value_type>
 GlobOutputIt copy(
- GlobInputIt /*in_first*/,
- GlobInputIt /*in_last*/,
- GlobOutputIt /*out_first*/)
+ GlobInputIt in_first,
+ GlobInputIt in_last,
+ GlobOutputIt out_first,
+ ActiveSource /*unused*/)
 {
  DASH_LOG_TRACE("dash::copy()", "blocking, global to global");
 
- // TODO:
- // - Implement adapter for local-to-global dash::copy here
- // - Return if global input range has no local sub-range
+ typedef typename GlobInputIt::size_type size_type;
+
+ size_type num_elem_total = dash::distance(in_first, in_last);
+ if (num_elem_total <= 0) {
+ DASH_LOG_TRACE("dash::copy", "input range empty");
+ return out_first;
+ }
+
+ internal::ContiguousRangeSet<GlobOutputIt> range_set{in_first, in_last};
+
+ const auto & in_team = in_first.team();
+ in_team.barrier();
+
+ std::vector<dart_handle_t> handles;
+ internal::local_copy_chunks<ValueType> local_chunks;
+
+ size_type num_elem_processed = 0;
+
+ for (auto range : range_set) {
+
+ auto cur_in_first = range.first;
+ auto num_copy_elem = range.second;
+
+ DASH_ASSERT_GT(num_copy_elem, 0,
+ "Number of elements to copy is 0");
+
+ // handle local data only
+ if (cur_in_first.is_local()) {
+ auto src_ptr = cur_in_first.local();
+ auto dest_ptr = out_first + num_elem_processed;
+ internal::copy_impl(src_ptr,
+ src_ptr + num_copy_elem,
+ dest_ptr,
+ &handles,
+ local_chunks);
+ }
+ num_elem_processed += num_copy_elem;
+ }
+
+ internal::do_local_copies(local_chunks);
+
+ if (!handles.empty()) {
+ DASH_LOG_TRACE("dash::copy", "Waiting for remote transfers to complete,",
+ "num_handles: ", handles.size());
+ dart_waitall(handles.data(), handles.size());
+ }
+ in_team.barrier();
+
+ DASH_ASSERT_EQ(num_elem_processed, num_elem_total,
+ "Failed to find all contiguous subranges in range");
 
- return GlobOutputIt();
+ return out_first + num_elem_total;
 }
 
 #endif // DOXYGEN