[Router] Enhanced the Connection Router by Optimizing the Heap Structure

.gitignore

@@ -155,3 +155,8 @@ tags
 cmake-build-debug
 cmake-build-release
 /.metadata/
+
+#
+# Clangd
+#
+compile_commands.json

doc/src/api/vpr/route_tree.rst

@@ -20,3 +20,10 @@ RouteTreeNode
 .. doxygenclass:: RouteTreeNode
    :project: vpr
    :members:
+
+RTExploredNode
+-------------
+
+.. doxygenclass:: RTExploredNode
+   :project: vpr
+   :members:

doc/src/api/vprinternals/router_heap.rst

@@ -2,30 +2,13 @@
 Router Heap
 ==============
 
-t_heap
-----------
-.. doxygenstruct:: t_heap
-   :project: vpr
-   :members:
-
 HeapInterface
 ----------
 .. doxygenclass:: HeapInterface
    :project: vpr
    :members:
 
-HeapStorage
-----------
-.. doxygenclass:: HeapStorage
-   :project: vpr
-   :members:
-
-KAryHeap
+DAryHeap
 ----------
-.. doxygenclass:: KAryHeap
+.. doxygenclass:: DAryHeap
    :project: vpr
-
-FourAryHeap
-----------
-.. doxygenclass:: FourAryHeap
-   :project: vpr

doc/src/vpr/command_line_usage.rst

@@ -1396,15 +1396,17 @@ The following options are only valid when the router is in timing-driven mode (t
 
     **Default:** ``safe``
 
-.. option:: --routing_budgets_algorithm { disable | minimax | scale_delay }
+.. option:: --routing_budgets_algorithm { disable | minimax | yoyo | scale_delay }
 
     .. warning:: Experimental
 
     Controls how the routing budgets are created. Routing budgets are used to guid VPR's routing algorithm to consider both short path and long path timing constraints :cite:`RCV_algorithm`.
 
     ``disable`` is used to disable the budget feature. This uses the default VPR and ignores hold time constraints.
 
-    ``minimax`` sets the minimum and maximum budgets by distributing the long path and short path slacks depending on the the current delay values. This uses the routing cost valleys and Minimax-PERT algorithm :cite:`minimax_pert,RCV_algorithm`.
+    ``minimax`` sets the minimum and maximum budgets by distributing the long path and short path slacks depending on the the current delay values. This uses the Minimax-PERT algorithm :cite:`minimax_pert`.
+
+    ``yoyo`` allocates budgets using minimax algorithm (as above), and enables hold slack resolution in the router using the Routing Cost Valleys (RCV) algorithm :cite:`RCV_algorithm`.
 
     ``scale_delay`` has the minimum budgets set to 0 and the maximum budgets is set to the delay of a net scaled by the pin criticality (net delay/pin criticality).
 

utils/route_diag/src/main.cpp

@@ -114,7 +114,7 @@ static void do_one_route(const Netlist<>& net_list,
             is_flat);
     enable_router_debug(router_opts, ParentNetId(), sink_node, 1, &router);
     bool found_path;
-    t_heap cheapest;
+    RTExploredNode cheapest;
     ConnectionParameters conn_params(ParentNetId::INVALID(),
                                      -1,
                                      false,

vpr/src/base/ShowSetup.cpp

@@ -468,9 +468,6 @@ static void ShowRouterOpts(const t_router_opts& RouterOpts) {
             case e_heap_type::FOUR_ARY_HEAP:
                 VTR_LOG("FOUR_ARY_HEAP\n");
                 break;
-            case e_heap_type::BUCKET_HEAP_APPROXIMATION:
-                VTR_LOG("BUCKET_HEAP_APPROXIMATION\n");
-                break;
             default:
                 VPR_FATAL_ERROR(VPR_ERROR_UNKNOWN, "Unknown router_heap\n");
         }

vpr/src/base/read_options.cpp

@@ -272,7 +272,7 @@ struct RouteBudgetsAlgorithm {
     }
 
     std::vector<std::string> default_choices() {
-        return {"minimax", "scale_delay", "disable"};
+        return {"minimax", "yoyo", "scale_delay", "disable"};
     }
 };
 
@@ -1063,8 +1063,6 @@ struct ParseRouterHeap {
             conv_value.set_value(e_heap_type::BINARY_HEAP);
         else if (str == "four_ary")
             conv_value.set_value(e_heap_type::FOUR_ARY_HEAP);
-        else if (str == "bucket")
-            conv_value.set_value(e_heap_type::BUCKET_HEAP_APPROXIMATION);
         else {
             std::stringstream msg;
             msg << "Invalid conversion from '" << str << "' to e_heap_type (expected one of: " << argparse::join(default_choices(), ", ") << ")";
@@ -1077,11 +1075,9 @@ struct ParseRouterHeap {
         ConvertedValue<std::string> conv_value;
         if (val == e_heap_type::BINARY_HEAP)
             conv_value.set_value("binary");
-        else if (val == e_heap_type::FOUR_ARY_HEAP)
-            conv_value.set_value("four_ary");
         else {
-            VTR_ASSERT(val == e_heap_type::BUCKET_HEAP_APPROXIMATION);
-            conv_value.set_value("bucket");
+            VTR_ASSERT(val == e_heap_type::FOUR_ARY_HEAP);
+            conv_value.set_value("four_ary");
         }
         return conv_value;
     }

vpr/src/base/read_route.cpp

@@ -20,7 +20,6 @@
 #include <ctime>
 #include <sstream>
 #include <string>
-#include <unordered_set>
 
 #include "atom_netlist.h"
 #include "atom_netlist_utils.h"
@@ -46,7 +45,6 @@
 #include "route_common.h"
 #include "route_tree.h"
 #include "read_route.h"
-#include "four_ary_heap.h"
 
 #include "old_traceback.h"
 

vpr/src/base/vpr_types.h

@@ -1607,14 +1607,18 @@ constexpr bool is_src_sink(e_rr_type type) { return (type == SOURCE || type == S
  *                     is being used.
  *   @param backward_path_cost  Total cost of the path up to and including this
  *                     node.
- *   @param occ        The current occupancy of the associated rr node
+ *   @param R_upstream Upstream resistance to ground from this node in the current
+ *                     path search (connection routing), including the resistance
+ *                     of the node itself (device_ctx.rr_nodes[index].R).
+ *   @param occ        The current occupancy of the associated rr node.
  */
 struct t_rr_node_route_inf {
     RREdgeId prev_edge;
 
     float acc_cost;
     float path_cost;
     float backward_path_cost;
+    float R_upstream;
 
   public: //Accessors
     short occ() const { return occ_; }