Faster check_non_configurable_edges

vpr/src/base/vpr_types.h

@@ -1637,7 +1637,7 @@ typedef t_routing_status<AtomNetId> t_atom_net_routing_status;
 
 /** Edge between two RRNodes */
 struct t_node_edge {
-    t_node_edge(RRNodeId fnode, RRNodeId tnode)
+    t_node_edge(RRNodeId fnode, RRNodeId tnode) noexcept
         : from_node(fnode)
         , to_node(tnode) {}
 
@@ -1650,10 +1650,18 @@ struct t_node_edge {
     }
 };
 
-///@brief Non-configurably connected nodes and edges in the RR graph
+/**
+ * @brief Groups of non-configurably connected nodes and edges in the RR graph.
+ * @note Each group is represented by a node set and an edge set, stored at the same index.
+ *
+ * For example, in an architecture with L-shaped wires formed by an x- and y-directed segment
+ * connected by an electrical short, each L-shaped wire corresponds to a new group. The group's
+ * index provides access to its node set (containing two RRNodeIds) and edge set (containing two
+ * directed edge in opposite directions).
+ */
 struct t_non_configurable_rr_sets {
-    std::set<std::set<RRNodeId>> node_sets;
-    std::set<std::set<t_node_edge>> edge_sets;
+    std::vector<std::set<RRNodeId>> node_sets;
+    std::vector<std::set<t_node_edge>> edge_sets;
 };
 
 ///@brief Power estimation options
@@ -1665,11 +1673,11 @@ struct t_power_opts {
  * @param max= Maximum channel width between x_max and y_max.
  * @param x_min= Minimum channel width of horizontal channels. Initialized when init_chan() is invoked in rr_graph2.cpp
  * @param y_min= Same as above but for vertical channels.
- * @param x_max= Maximum channel width of horiozntal channels. Initialized when init_chan() is invoked in rr_graph2.cpp
+ * @param x_max= Maximum channel width of horizontal channels. Initialized when init_chan() is invoked in rr_graph2.cpp
  * @param y_max= Same as above but for vertical channels.
  * @param x_list= Stores the channel width of all horizontal channels and thus goes from [0..grid.height()]
  * (imagine a 2D Cartesian grid with horizontal lines starting at every grid point on a line parallel to the y-axis)
- * @param y_list= Stores the channel width of all verical channels and thus goes from [0..grid.width()]
+ * @param y_list= Stores the channel width of all vertical channels and thus goes from [0..grid.width()]
  * (imagine a 2D Cartesian grid with vertical lines starting at every grid point on a line parallel to the x-axis)
  */
 

vpr/src/route/check_route.cpp

@@ -1,4 +1,5 @@
-#include <cstdio>
+
+#include "check_route.h"
 
 #include "route_common.h"
 #include "vtr_assert.h"
@@ -11,7 +12,7 @@
 
 #include "globals.h"
 #include "route_export.h"
-#include "check_route.h"
+
 #include "rr_graph.h"
 #include "check_rr_graph.h"
 #include "read_xml_arch_file.h"
@@ -39,11 +40,32 @@ static void check_locally_used_clb_opins(const t_clb_opins_used& clb_opins_used_
                                          enum e_route_type route_type,
                                          bool is_flat);
 
+/**
+ * Checks that all non-configurable edges are in a legal configuration.
+ * @param net_list The netlist whose routing is to be checked.
+ * @param is_flat True if flat routing is enabled; otherwise false.
+ */
 static void check_all_non_configurable_edges(const Netlist<>& net_list, bool is_flat);
+
+/**
+ * @brief Checks that the specified routing is legal with respect to non-configurable edges.
+ * For routing to be valid, if any non-configurable edge is used, all  nodes in the same set
+ * and the required connecting edges in the set must also be used.
+ *
+ * @param net_list A reference to the netlist.
+ * @param net The net id for which the check is done.
+ * @param non_configurable_rr_sets Node and edge sets that constitute non-configurable RR sets.
+ * @param rrnode_set_id Specifies which RR sets each RR node is part of. These indices can be used to
+ * access elements of node_sets and edge_sets in non_configurable_rr_sets.
+ * @param is_flat Indicates whether flat routing is enabled.
+ * @return True if check is done successfully; otherwise false.
+ */
 static bool check_non_configurable_edges(const Netlist<>& net_list,
                                          ParentNetId net,
                                          const t_non_configurable_rr_sets& non_configurable_rr_sets,
+                                         const vtr::vector<RRNodeId, int>& rrnode_set_id,
                                          bool is_flat);
+
 static void check_net_for_stubs(const Netlist<>& net_list,
                                 ParentNetId net,
                                 bool is_flat);
@@ -65,13 +87,9 @@ void check_route(const Netlist<>& net_list,
         return;
     }
 
-    int max_pins;
-    unsigned int ipin;
-    bool valid, connects;
-
-    auto& device_ctx = g_vpr_ctx.device();
+    const auto& device_ctx = g_vpr_ctx.device();
     const auto& rr_graph = device_ctx.rr_graph;
-    auto& route_ctx = g_vpr_ctx.routing();
+    const auto& route_ctx = g_vpr_ctx.routing();
 
     const size_t num_switches = rr_graph.num_rr_switches();
 
@@ -83,7 +101,7 @@ void check_route(const Netlist<>& net_list,
      * is a successful routing, but I want to double check it here.          */
 
     recompute_occupancy_from_scratch(net_list, is_flat);
-    valid = feasible_routing();
+    const bool valid = feasible_routing();
     if (valid == false) {
         VPR_ERROR(VPR_ERROR_ROUTE,
                   "Error in check_route -- routing resources are overused.\n");
@@ -95,7 +113,7 @@ void check_route(const Netlist<>& net_list,
                                      is_flat);
     }
 
-    max_pins = 0;
+    int max_pins = 0;
     for (auto net_id : net_list.nets())
         max_pins = std::max(max_pins, (int)net_list.net_pins(net_id).size());
 
@@ -129,7 +147,7 @@ void check_route(const Netlist<>& net_list,
             check_switch(rt_node, num_switches);
 
             if (rt_node.parent()) {
-                connects = check_adjacent(rt_node.parent()->inode, rt_node.inode, is_flat);
+                bool connects = check_adjacent(rt_node.parent()->inode, rt_node.inode, is_flat);
                 if (!connects) {
                     VPR_ERROR(VPR_ERROR_ROUTE,
                               "in check_route: found non-adjacent segments in traceback while checking net %d:\n"
@@ -154,7 +172,7 @@ void check_route(const Netlist<>& net_list,
                             num_sinks, net_list.net_sinks(net_id).size());
         }
 
-        for (ipin = 0; ipin < net_list.net_pins(net_id).size(); ipin++) {
+        for (size_t ipin = 0; ipin < net_list.net_pins(net_id).size(); ipin++) {
             if (pin_done[ipin] == false) {
                 VPR_FATAL_ERROR(VPR_ERROR_ROUTE,
                                 "in check_route: net %zu does not connect to pin %d.\n", size_t(net_id), ipin);
@@ -194,7 +212,7 @@ static void check_sink(const Netlist<>& net_list,
                         inode, net_list.net_name(net_id).c_str(), size_t(net_id));
     }
 
-    VTR_ASSERT(!pin_done[net_pin_index]); /* Should not have found a routed cnnection to it before */
+    VTR_ASSERT(!pin_done[net_pin_index]); /* Should not have found a routed connection to it before */
     pin_done[net_pin_index] = true;
 }
 
@@ -595,43 +613,71 @@ static void check_node_and_range(RRNodeId inode,
                   is_flat);
 }
 
-//Checks that all non-configurable edges are in a legal configuration
-//This check is slow, so it has been moved out of check_route()
 static void check_all_non_configurable_edges(const Netlist<>& net_list, bool is_flat) {
+    const auto& rr_graph = g_vpr_ctx.device().rr_graph;
+
     vtr::ScopedStartFinishTimer timer("Checking to ensure non-configurable edges are legal");
-    auto non_configurable_rr_sets = identify_non_configurable_rr_sets();
+    const t_non_configurable_rr_sets non_configurable_rr_sets = identify_non_configurable_rr_sets();
+
+    // Specifies which RR set each node is part of.
+    vtr::vector<RRNodeId, int> rrnode_set_ids(rr_graph.num_nodes(), -1);
+
+    const size_t num_non_cfg_rr_sets = non_configurable_rr_sets.node_sets.size();
+
+    // Populate rrnode_set_ids
+    for (size_t non_cfg_rr_set_id = 0; non_cfg_rr_set_id < num_non_cfg_rr_sets; non_cfg_rr_set_id++) {
+        const std::set<RRNodeId>& node_set = non_configurable_rr_sets.node_sets[non_cfg_rr_set_id];
+        for (const RRNodeId node_id : node_set) {
+            VTR_ASSERT_SAFE(rrnode_set_ids[node_id] == -1);
+            rrnode_set_ids[node_id] = (int)non_cfg_rr_set_id;
+        }
+    }
 
     for (auto net_id : net_list.nets()) {
         check_non_configurable_edges(net_list,
                                      net_id,
                                      non_configurable_rr_sets,
+                                     rrnode_set_ids,
                                      is_flat);
     }
 }
 
-// Checks that the specified routing is legal with respect to non-configurable edges
-//
-//For routing to be legal if *any* non-configurable edge is used, so must *all*
-//other non-configurable edges in the same set
 static bool check_non_configurable_edges(const Netlist<>& net_list,
                                          ParentNetId net,
                                          const t_non_configurable_rr_sets& non_configurable_rr_sets,
+                                         const vtr::vector<RRNodeId, int>& rrnode_set_id,
                                          bool is_flat) {
     const auto& device_ctx = g_vpr_ctx.device();
-    auto& route_ctx = g_vpr_ctx.mutable_routing();
+    const auto& route_ctx = g_vpr_ctx.routing();
 
     if (!route_ctx.route_trees[net]) // no routing
         return true;
 
-    // Collect all the edges used by this net's routing
+    // Collect all the nodes, edges, and non-configurable RR set ids used by this net's routing
     std::set<t_node_edge> routing_edges;
     std::set<RRNodeId> routing_nodes;
-    for (auto& rt_node : route_ctx.route_trees[net].value().all_nodes()) {
+    std::set<int> routing_non_configurable_rr_set_ids;
+    for (const RouteTreeNode& rt_node : route_ctx.route_trees[net].value().all_nodes()) {
         routing_nodes.insert(rt_node.inode);
         if (!rt_node.parent())
             continue;
         t_node_edge edge = {rt_node.parent()->inode, rt_node.inode};
         routing_edges.insert(edge);
+
+        if (rrnode_set_id[rt_node.inode] >= 0) {    // The node belongs to a non-configurable RR set
+            routing_non_configurable_rr_set_ids.insert(rrnode_set_id[rt_node.inode]);
+        }
+    }
+
+    // Copy used non-configurable RR sets
+    // This is done to check legality only for used non-configurable RR sets. If a non-configurable RR set
+    // is not used by a net's routing, it cannot violate the requirements of using that non-configurable RR set.
+    t_non_configurable_rr_sets used_non_configurable_rr_sets;
+    used_non_configurable_rr_sets.node_sets.reserve(routing_non_configurable_rr_set_ids.size());
+    used_non_configurable_rr_sets.edge_sets.reserve(routing_non_configurable_rr_set_ids.size());
+    for (const int set_idx : routing_non_configurable_rr_set_ids) {
+        used_non_configurable_rr_sets.node_sets.emplace_back(non_configurable_rr_sets.node_sets[set_idx]);
+        used_non_configurable_rr_sets.edge_sets.emplace_back(non_configurable_rr_sets.edge_sets[set_idx]);
     }
 
     //We need to perform two types of checks:
@@ -640,13 +686,13 @@ static bool check_non_configurable_edges(const Netlist<>& net_list,
     // 2) That all (required) non-configurable edges are used
     //
     //We need to check (2) in addition to (1) to ensure that (1) did not pass
-    //because the nodes 'happend' to be connected together by configurable
+    //because the nodes 'happened' to be connected together by configurable
     //routing (to be legal, by definition, they must be connected by
     //non-configurable routing).
 
-    //Check that all nodes in each non-configurable set are full included if any element
+    //Check that all nodes in each non-configurable set are fully included if any element
     //within a set is used by the routing
-    for (const auto& rr_nodes : non_configurable_rr_sets.node_sets) {
+    for (const auto& rr_nodes : used_non_configurable_rr_sets.node_sets) {
         //Compute the intersection of the routing and current non-configurable nodes set
         std::vector<RRNodeId> intersection;
         std::set_intersection(routing_nodes.begin(), routing_nodes.end(),
@@ -668,7 +714,7 @@ static bool check_non_configurable_edges(const Netlist<>& net_list,
                                     routing_nodes.begin(), routing_nodes.end(),
                                     std::back_inserter(difference));
 
-                VTR_ASSERT(difference.size() > 0);
+                VTR_ASSERT(!difference.empty());
                 std::string msg = vtr::string_fmt(
                     "Illegal routing for net '%s' (#%zu) some "
                     "required non-configurably connected nodes are missing:\n",
@@ -685,7 +731,7 @@ static bool check_non_configurable_edges(const Netlist<>& net_list,
 
     //Check that any sets of non-configurable RR graph edges are fully included
     //in the routing, if any of a set's edges are used
-    for (const auto& rr_edges : non_configurable_rr_sets.edge_sets) {
+    for (const auto& rr_edges : used_non_configurable_rr_sets.edge_sets) {
         //Compute the intersection of the routing and current non-configurable edge set
         std::vector<t_node_edge> intersection;
         std::set_intersection(routing_edges.begin(), routing_edges.end(),
@@ -698,7 +744,7 @@ static bool check_non_configurable_edges(const Netlist<>& net_list,
             //Since at least one non-configurable edge is used, to be legal
             //the full set of non-configurably connected edges must be used.
             //
-            //This is somewhat complicted by the fact that non-configurable edges
+            //This is somewhat complicated by the fact that non-configurable edges
             //are sometimes bi-directional (e.g. electrical shorts) and so appear
             //in rr_edges twice (once forward, once backward). Only one of the
             //paired edges need appear to be correct.
@@ -791,9 +837,9 @@ class StubFinder {
     std::set<int> stub_nodes_;
 };
 
-//Cheks for stubs in a net's routing.
+//Checks for stubs in a net's routing.
 //
-//Stubs (routing branches which don't connect to SINKs) serve no purpose, and only chew up wiring unecessarily.
+//Stubs (routing branches which don't connect to SINKs) serve no purpose, and only chew up wiring unnecessarily.
 //The only exception are stubs required by non-configurable switches (e.g. shorts).
 //
 //We treat any configurable stubs as an error.

vpr/src/route/edge_groups.cpp

@@ -52,14 +52,14 @@ t_non_configurable_rr_sets EdgeGroups::output_sets() {
         std::set<t_node_edge> edge_set;
         std::set<RRNodeId> node_set(nodes.begin(), nodes.end());
 
-        for (const auto& src : node_set) {
-            for (const auto& dest : graph_[src].edges) {
-                edge_set.emplace(t_node_edge(src, dest));
+        for (const RRNodeId src : node_set) {
+            for (const RRNodeId dest : graph_[src].edges) {
+                edge_set.emplace(src, dest);
             }
         }
 
-        sets.node_sets.emplace(std::move(node_set));
-        sets.edge_sets.emplace(std::move(edge_set));
+        sets.node_sets.emplace_back(std::move(node_set));
+        sets.edge_sets.emplace_back(std::move(edge_set));
     }
 
     return sets;

vpr/test/test_edge_groups.cpp

@@ -19,12 +19,12 @@ TEST_CASE("edge_groups_create_sets", "[vpr]") {
     // Build chains from the given connected sets
     int max_node_id = 0;
     std::vector<std::pair<int, int>> edges;
-    for (auto set : connected_sets) {
+    for (const auto& set : connected_sets) {
         int last = *set.cbegin();
         std::for_each(std::next(set.cbegin()),
                       set.cend(),
                       [&](int node) {
-                          edges.push_back(std::make_pair(last, node));
+                          edges.emplace_back(last, node);
                           last = node;
                           max_node_id = std::max(max_node_id, node);
                       });
@@ -36,7 +36,7 @@ TEST_CASE("edge_groups_create_sets", "[vpr]") {
     // Initialize nodes to [0, 1, ..., max_node_id]
     std::iota(nodes.begin(), nodes.end(), 0);
 
-    // Create a Mersenne Twister psuedo-random number generator with seed 1
+    // Create a Mersenne Twister pseudo-random number generator with seed 1
     std::mt19937 g(1);
 
     // Run the test many times, the PRNG will give differently shuffled inputs
@@ -66,12 +66,12 @@ TEST_CASE("edge_groups_create_sets", "[vpr]") {
         t_non_configurable_rr_sets sets = groups.output_sets();
 
         // Check for the expected sets
-        for (auto set : connected_sets) {
+        for (const auto& set : connected_sets) {
             std::set<RRNodeId> random_set;
             for (auto elem : set) {
                 random_set.insert(RRNodeId(random_nodes[elem]));
             }
-            REQUIRE(sets.node_sets.find(random_set) != sets.node_sets.end());
+            REQUIRE(std::find(sets.node_sets.begin(), sets.node_sets.end(), random_set) != sets.node_sets.end());
         }
     }
 }