Merge pull request #2870 from AlexandreSinger/feature-appack

[APPack] Added Flat Placement Reconstruction

Author: AlexandreSinger

vpr/src/base/load_flat_place.cpp

@@ -10,14 +10,37 @@
 
 #include <fstream>
 #include <unordered_set>
+#include "atom_lookup.h"
 #include "atom_netlist.h"
 #include "clustered_netlist.h"
 #include "FlatPlacementInfo.h"
 #include "globals.h"
 #include "vpr_context.h"
 #include "vpr_error.h"
 #include "vpr_types.h"
+#include "vtr_assert.h"
 #include "vtr_log.h"
+#include "vtr_vector_map.h"
+#include "vtr_version.h"
+
+/**
+ * @brief Prints the header for the flat placement file. This includes helpful
+ *        information on how to read the file and when it was generated.
+ *
+ *  @param fp
+ *          File pointer to the file the cluster is printed to.
+ */
+static void print_flat_placement_file_header(FILE* fp) {
+    fprintf(fp, "# Flat Placement File\n");
+    fprintf(fp, "# Auto-generated by VPR %s\n",
+            vtr::VERSION);
+    fprintf(fp, "# Created: %s\n",
+            vtr::BUILD_TIMESTAMP);
+    fprintf(fp, "#\n");
+    fprintf(fp, "# This file prints the following information for each atom in the netlist:\n");
+    fprintf(fp, "# <atom_name> <x> <y> <layer> <atom_sub_tile> <atom_site_idx> #<clb_blk_id> <atom_pb_type>\n");
+    fprintf(fp, "\n");
+}
 
 /**
  * @brief Prints flat placement file entries for the atoms in one placed
@@ -73,6 +96,9 @@ void write_flat_placement(const char* flat_place_file_path,
     // Create a file in write mode for the flat placement.
     FILE* fp = fopen(flat_place_file_path, "w");
 
+    // Add a header to the flat placement file.
+    print_flat_placement_file_header(fp);
+
     // For each cluster, write out the atoms in the cluster at this cluster's
     // location.
     for (ClusterBlockId iblk : cluster_netlist.blocks()) {
@@ -174,3 +200,118 @@ bool load_flat_placement(t_vpr_setup& vpr_setup, const t_arch& arch) {
     return false;
 }
 
+void log_flat_placement_reconstruction_info(
+                            const FlatPlacementInfo& flat_placement_info,
+                            const vtr::vector_map<ClusterBlockId, t_block_loc>& block_locs,
+                            const vtr::vector<ClusterBlockId, std::unordered_set<AtomBlockId>>& atoms_lookup,
+                            const AtomLookup& cluster_of_atom_lookup,
+                            const AtomNetlist& atom_netlist,
+                            const ClusteredNetlist& clustered_netlist) {
+    // Go through each cluster and see how many clusters have atoms that
+    // do not belong (cluster is imperfect).
+    unsigned num_imperfect_clusters = 0;
+    for (ClusterBlockId clb_blk_id : clustered_netlist.blocks()) {
+        // Get the centroid of the cluster
+        const auto& clb_atoms = atoms_lookup[clb_blk_id];
+        float centroid_x = 0.f;
+        float centroid_y = 0.f;
+        float centroid_layer = 0.f;
+        float centroid_sub_tile = 0.f;
+        for (AtomBlockId atom_blk_id : clb_atoms) {
+            // TODO: Currently only handle the case when all of the position
+            //       data is provided. This can be extended,
+            VTR_ASSERT(flat_placement_info.blk_x_pos[atom_blk_id] != FlatPlacementInfo::UNDEFINED_POS);
+            VTR_ASSERT(flat_placement_info.blk_y_pos[atom_blk_id] != FlatPlacementInfo::UNDEFINED_POS);
+            VTR_ASSERT(flat_placement_info.blk_layer[atom_blk_id] != FlatPlacementInfo::UNDEFINED_POS);
+            VTR_ASSERT(flat_placement_info.blk_sub_tile[atom_blk_id] != FlatPlacementInfo::UNDEFINED_SUB_TILE);
+
+            centroid_x += flat_placement_info.blk_x_pos[atom_blk_id];
+            centroid_y += flat_placement_info.blk_y_pos[atom_blk_id];
+            centroid_layer += flat_placement_info.blk_layer[atom_blk_id];
+            centroid_sub_tile += flat_placement_info.blk_sub_tile[atom_blk_id];
+        }
+        centroid_x /= static_cast<float>(clb_atoms.size());
+        centroid_y /= static_cast<float>(clb_atoms.size());
+        centroid_layer /= static_cast<float>(clb_atoms.size());
+        centroid_sub_tile /= static_cast<float>(clb_atoms.size());
+        // Check if every atom in the cluster is within 0.5 units of the
+        // centroid.
+        for (AtomBlockId atom_blk_id : clb_atoms) {
+            // If the atom's flat placement more than half a block in any
+            // direction from the flat placement centroid, then it does not
+            // want to be in this cluster.
+            // FIXME: This should take into account large blocks somehow, just
+            //        being 0.5 tiles away may not be sufficient.
+            if (std::abs(centroid_x - flat_placement_info.blk_x_pos[atom_blk_id]) > 0.5f ||
+                std::abs(centroid_y - flat_placement_info.blk_y_pos[atom_blk_id]) > 0.5f ||
+                std::abs(centroid_layer - flat_placement_info.blk_layer[atom_blk_id]) > 0.5f ||
+                std::abs(centroid_sub_tile - flat_placement_info.blk_sub_tile[atom_blk_id]) > 0.5f) {
+                num_imperfect_clusters++;
+                break;
+            }
+        }
+    }
+    // Go through each atom and compute how much it has displaced and count
+    // how many have been displaced beyond some threshold.
+    constexpr float disp_threashold = 0.5f;
+    float total_disp = 0;
+    unsigned num_atoms_missplaced = 0;
+    for (AtomBlockId atom_blk_id : atom_netlist.blocks()) {
+        // TODO: Currently only handle the case when all of the position
+        //       data is provided. This can be extended,
+        VTR_ASSERT(flat_placement_info.blk_x_pos[atom_blk_id] != FlatPlacementInfo::UNDEFINED_POS);
+        VTR_ASSERT(flat_placement_info.blk_y_pos[atom_blk_id] != FlatPlacementInfo::UNDEFINED_POS);
+        VTR_ASSERT(flat_placement_info.blk_layer[atom_blk_id] != FlatPlacementInfo::UNDEFINED_POS);
+        VTR_ASSERT(flat_placement_info.blk_sub_tile[atom_blk_id] != FlatPlacementInfo::UNDEFINED_SUB_TILE);
+
+        // Get the (x, y, layer) position of the block.
+        int blk_x = flat_placement_info.blk_x_pos[atom_blk_id];
+        int blk_y = flat_placement_info.blk_y_pos[atom_blk_id];
+        int blk_layer = flat_placement_info.blk_layer[atom_blk_id];
+
+        // Get the (x, y, layer) position of the cluster that contains this block.
+        ClusterBlockId atom_clb_id = cluster_of_atom_lookup.atom_clb(atom_blk_id);
+        const t_block_loc& clb_loc = block_locs[atom_clb_id];
+
+        // Compute the distance between these two positions.
+        // FIXME: This will overreport large blocks. This should really be
+        //        the distance outside of the tile you want to be placed in.
+        float dx = blk_x - clb_loc.loc.x;
+        float dy = blk_y - clb_loc.loc.y;
+        float dlayer = blk_layer - clb_loc.loc.layer;
+        float dist = std::sqrt((dx * dx) + (dy * dy) + (dlayer * dlayer));
+
+        // Accumulate into the total displacement.
+        total_disp += dist;
+
+        // Check if this block has been displaced beyond the threshold.
+        if (dist >= disp_threashold) {
+            num_atoms_missplaced++;
+        }
+
+        // TODO: Make this debug option of higher verbosity. Helpful for
+        //       debugging flat placement reconstruction.
+        /*
+        VTR_LOG("%s %d %d %d %d\n",
+                g_vpr_ctx.atom().nlist.block_name(atom_blk_id).c_str(),
+                clb_loc.loc.x,
+                clb_loc.loc.y,
+                clb_loc.loc.layer,
+                clb_loc.loc.sub_tile);
+        */
+    }
+
+    // Log the flat placement reconstruction info.
+    size_t num_atoms = atom_netlist.blocks().size();
+    size_t num_clusters = clustered_netlist.blocks().size();
+    VTR_LOG("Flat Placement Reconstruction Info:\n");
+    VTR_LOG("\tPercent of clusters with reconstruction errors: %f\n",
+            static_cast<float>(num_imperfect_clusters) / static_cast<float>(num_clusters));
+    VTR_LOG("\tTotal displacement of initial placement from flat placement: %f\n",
+            total_disp);
+    VTR_LOG("\tAverage atom displacement of initial placement from flat placement: %f\n",
+            total_disp / static_cast<float>(num_atoms));
+    VTR_LOG("\tPercent of atoms misplaced from the flat placement: %f\n",
+            static_cast<float>(num_atoms_missplaced) / static_cast<float>(num_atoms));
+}
+

vpr/src/base/load_flat_place.h

@@ -17,6 +17,7 @@
 
 // Forward declarations
 class AtomBlockId;
+class AtomLookup;
 class AtomNetlist;
 class ClusterBlockId;
 class ClusteredNetlist;
@@ -61,3 +62,29 @@ FlatPlacementInfo read_flat_placement(const std::string& read_flat_place_file_pa
  */
 bool load_flat_placement(t_vpr_setup& vpr_setup, const t_arch& arch);
 
+/**
+ * @brief Logs information on the quality of the clustering and placement
+ *        reconstruction of the given flat placement.
+ *
+ *  @param flat_placement_info
+ *                  The flat placement to log,
+ *  @param block_locs
+ *                  The location of each cluster in the netlist.
+ *  @param atoms_lookup
+ *                  A lookup between each cluster and the atoms it contains.
+ *  @param cluster_of_atom_lookup
+ *                  A lookup between each atom and the cluster that contains it.
+ *  @param atom_netlist
+ *                  The netlist of atoms the flat placement was over.
+ *  @param clustered_netlist
+ *                  The clustered netlist that the flat placement was used to
+ *                  generate.
+ */
+void log_flat_placement_reconstruction_info(
+                const FlatPlacementInfo& flat_placement_info,
+                const vtr::vector_map<ClusterBlockId, t_block_loc>& block_locs,
+                const vtr::vector<ClusterBlockId, std::unordered_set<AtomBlockId>>& atoms_lookup,
+                const AtomLookup& cluster_of_atom_lookup,
+                const AtomNetlist& atom_netlist,
+                const ClusteredNetlist& clustered_netlist);
+

vpr/src/base/place_and_route.cpp

@@ -4,6 +4,7 @@
 #include <cmath>
 #include <algorithm>
 
+#include "FlatPlacementInfo.h"
 #include "vtr_assert.h"
 #include "vtr_log.h"
 
@@ -173,6 +174,7 @@ int binary_search_place_and_route(const Netlist<>& placement_net_list,
                       det_routing_arch,
                       segment_inf,
                       arch->directs,
+                      FlatPlacementInfo(),  // Pass empty flat placement info.
                       /*is_flat=*/false);
         }
         success = route(router_net_list,
@@ -311,6 +313,7 @@ int binary_search_place_and_route(const Netlist<>& placement_net_list,
                 try_place(placement_net_list, placer_opts, router_opts, analysis_opts, noc_opts,
                           arch->Chans, det_routing_arch, segment_inf,
                           arch->directs,
+                          FlatPlacementInfo(),  // Pass empty flat placement info.
                           /*is_flat=*/false);
             }
 

vpr/src/base/vpr_api.cpp

@@ -688,18 +688,19 @@ bool vpr_pack(t_vpr_setup& vpr_setup, const t_arch& arch) {
                                  + wtoi_switch_del); /* multiply by 4 to get a more conservative estimate */
     }
 
-    // Read in the flat placement if a flat placement file is provided.
-    FlatPlacementInfo flat_placement_info;
-    if (!vpr_setup.FileNameOpts.read_flat_place_file.empty()) {
-        flat_placement_info = read_flat_placement(
+    // Read in the flat placement if a flat placement file is provided and it
+    // has not been loaded already.
+    if (!vpr_setup.FileNameOpts.read_flat_place_file.empty() &&
+        !g_vpr_ctx.atom().flat_placement_info.valid) {
+        g_vpr_ctx.mutable_atom().flat_placement_info = read_flat_placement(
                                     vpr_setup.FileNameOpts.read_flat_place_file,
                                     g_vpr_ctx.atom().nlist);
     }
 
     return try_pack(&vpr_setup.PackerOpts, &vpr_setup.AnalysisOpts,
                     &arch, vpr_setup.user_models,
                     vpr_setup.library_models, inter_cluster_delay,
-                    vpr_setup.PackerRRGraph, flat_placement_info);
+                    vpr_setup.PackerRRGraph, g_vpr_ctx.atom().flat_placement_info);
 }
 
 void vpr_load_packing(t_vpr_setup& vpr_setup, const t_arch& arch) {
@@ -849,6 +850,15 @@ void vpr_place(const Netlist<>& net_list, t_vpr_setup& vpr_setup, const t_arch&
             is_flat);
     }
 
+    // Read in the flat placement if a flat placement file is provided and it
+    // has not been loaded already.
+    if (!vpr_setup.FileNameOpts.read_flat_place_file.empty() &&
+        !g_vpr_ctx.atom().flat_placement_info.valid) {
+        g_vpr_ctx.mutable_atom().flat_placement_info = read_flat_placement(
+                                    vpr_setup.FileNameOpts.read_flat_place_file,
+                                    g_vpr_ctx.atom().nlist);
+    }
+
     try_place(net_list,
               vpr_setup.PlacerOpts,
               vpr_setup.RouterOpts,
@@ -858,6 +868,7 @@ void vpr_place(const Netlist<>& net_list, t_vpr_setup& vpr_setup, const t_arch&
               &vpr_setup.RoutingArch,
               vpr_setup.Segments,
               arch.directs,
+              g_vpr_ctx.atom().flat_placement_info,
               is_flat);
 
     auto& filename_opts = vpr_setup.FileNameOpts;

vpr/src/base/vpr_context.h

@@ -5,6 +5,7 @@
 #include <vector>
 #include <mutex>
 
+#include "FlatPlacementInfo.h"
 #include "prepack.h"
 #include "vpr_types.h"
 #include "vtr_ndmatrix.h"
@@ -79,6 +80,10 @@ struct AtomContext : public Context {
 
     /// @brief Mappings to/from the Atom Netlist to physically described .blif models
     AtomLookup lookup;
+
+    /// @brief Placement information on each atom known (from a file or another
+    ///        algorithm) before packing and the cluster-level placement.
+    FlatPlacementInfo flat_placement_info;
 };
 
 /**