Merge pull request #1802 from verilog-to-routing/cluster_attraction_groups

Cluster attraction groups

Author: vaughnbetz

vpr/src/base/SetupVPR.cpp

@@ -495,6 +495,7 @@ void SetupPackerOpts(const t_options& Options,
     PackerOpts->high_fanout_threshold = Options.pack_high_fanout_threshold;
     PackerOpts->transitive_fanout_threshold = Options.pack_transitive_fanout_threshold;
     PackerOpts->feasible_block_array_size = Options.pack_feasible_block_array_size;
+    PackerOpts->use_attraction_groups = Options.use_attraction_groups;
 
     //TODO: document?
     PackerOpts->inter_cluster_net_delay = 1.0; /* DEFAULT */

vpr/src/base/read_options.cpp

@@ -1638,6 +1638,11 @@ argparse::ArgumentParser create_arg_parser(std::string prog_name, t_options& arg
         .default_value("2")
         .show_in(argparse::ShowIn::HELP_ONLY);
 
+    pack_grp.add_argument<bool, ParseOnOff>(args.use_attraction_groups, "--use_attraction_groups")
+        .help("Whether attraction groups are used to make it easier to pack primitives in the same floorplan region together.")
+        .default_value("on")
+        .show_in(argparse::ShowIn::HELP_ONLY);
+
     auto& place_grp = parser.add_argument_group("placement options");
 
     place_grp.add_argument(args.Seed, "--seed")

vpr/src/base/read_options.h

@@ -91,6 +91,7 @@ struct t_options {
     argparse::ArgValue<int> pack_feasible_block_array_size;
     argparse::ArgValue<std::vector<std::string>> pack_high_fanout_threshold;
     argparse::ArgValue<int> pack_verbosity;
+    argparse::ArgValue<bool> use_attraction_groups;
 
     /* Placement options */
     argparse::ArgValue<int> Seed;

vpr/src/base/vpr_types.h

@@ -814,6 +814,7 @@ struct t_packer_opts {
     enum e_packer_algorithm packer_algorithm;
     std::string device_layout;
     e_timing_update_type timing_update_type;
+    bool use_attraction_groups;
 };
 
 /**

vpr/src/pack/attraction_groups.cpp

@@ -0,0 +1,54 @@
+#include "attraction_groups.h"
+
+AttractionInfo::AttractionInfo(bool attraction_groups_on) {
+    auto& floorplanning_ctx = g_vpr_ctx.mutable_floorplanning();
+    auto& atom_ctx = g_vpr_ctx.atom();
+    int num_parts = floorplanning_ctx.constraints.get_num_partitions();
+
+    //Initialize every atom to have no attraction group id
+    int num_atoms = atom_ctx.nlist.blocks().size();
+
+    atom_attraction_group.resize(num_atoms);
+    fill(atom_attraction_group.begin(), atom_attraction_group.end(), AttractGroupId::INVALID());
+
+    /*
+     * Create an attraction group for each partition in the floorplanning constraints
+     * if the packer option for attraction groups is turned on.
+     */
+    if (attraction_groups_on) {
+        for (int ipart = 0; ipart < num_parts; ipart++) {
+            PartitionId partid(ipart);
+            Partition part = floorplanning_ctx.constraints.get_partition(partid);
+
+            AttractionGroup group_info;
+            group_info.group_atoms = floorplanning_ctx.constraints.get_part_atoms(partid);
+
+            attraction_groups.push_back(group_info);
+        }
+
+        //Then, fill in the group id for the atoms that do have an attraction group
+        int num_att_grps = attraction_groups.size();
+
+        for (int igroup = 0; igroup < num_att_grps; igroup++) {
+            AttractGroupId group_id(igroup);
+
+            AttractionGroup att_group = attraction_groups[group_id];
+
+            for (unsigned int iatom = 0; iatom < att_group.group_atoms.size(); iatom++) {
+                atom_attraction_group[att_group.group_atoms[iatom]] = group_id;
+            }
+        }
+    }
+}
+
+const AttractionGroup& AttractionInfo::get_attraction_group_info(const AttractGroupId group_id) {
+    return attraction_groups[group_id];
+}
+
+void AttractionInfo::set_attraction_group_info(AttractGroupId group_id, const AttractionGroup& group_info) {
+    attraction_groups[group_id] = group_info;
+}
+
+void AttractionInfo::add_attraction_group(const AttractionGroup& group_info) {
+    attraction_groups.push_back(group_info);
+}

vpr/src/pack/attraction_groups.h

@@ -0,0 +1,108 @@
+/*
+ * attraction_groups.h
+ *
+ *  Created on: Jun. 13, 2021
+ *      Author: khalid88
+ */
+
+#ifndef VPR_SRC_PACK_ATTRACTION_GROUPS_H_
+#define VPR_SRC_PACK_ATTRACTION_GROUPS_H_
+
+#include "vtr_strong_id.h"
+#include "vtr_vector.h"
+#include "atom_netlist.h"
+#include "globals.h"
+
+/**
+ * @file
+ * @brief This file defines the AttractionInfo class, which is used to store atoms in attraction groups, which are
+ *        used during the clustering process.
+ *
+ * Overview
+ * ========
+ * Attraction groups are used during the clustering process. Atoms in the same attraction groups will be highly desirable to
+ * be packed together. If an atom is in the same attraction group as an atoms already in the cluster, its gain will be increased
+ * to reflect the increased desire to pack atoms of the same attraction group together. Currently, the attraction groups are created
+ * based on which atoms are in the same Partition, from floorplanning constraints. In the future, attraction groups can be used to
+ * pack atoms together based on other concepts.
+ */
+
+/// @brief Type tag for AttractGroupId
+struct attraction_id_tag;
+
+/// @brief A unique identifier for an attraction group.
+typedef vtr::StrongId<attraction_id_tag> AttractGroupId;
+
+struct AttractionGroup {
+    //stores all atoms in the attraction group
+    std::vector<AtomBlockId> group_atoms;
+
+    /*
+     * Atoms belonging to this attraction group will receive this gain if they
+     * are potential candidates to be put in a cluster with the same attraction group.
+     */
+    float gain = 5;
+
+    /*
+     * If the group is made up from a partition of atoms that are confined to a size one spot
+     * (i.e. one x, y grid location), the clusterer will immediately put all atoms in the group
+     * into the same cluster
+     */
+    /* TODO: Add the code in the clusterer that will do the above steps. */
+    //bool must_be_packed_in_one_cluster = false;
+};
+
+class AttractionInfo {
+  public:
+    //Constructor that fills in the attraction groups based on vpr's floorplan constraints.
+    //If no constraints were specified, then no attraction groups will be created.
+    AttractionInfo(bool attraction_groups_on);
+
+    //Setters and getters for the class
+    AttractGroupId get_atom_attraction_group(const AtomBlockId atom_id);
+
+    const AttractionGroup& get_attraction_group_info(const AttractGroupId group_id);
+
+    void set_atom_attraction_group(const AtomBlockId atom_id, const AttractGroupId group_id);
+
+    void set_attraction_group_info(AttractGroupId group_id, const AttractionGroup& group_info);
+
+    float get_attraction_group_gain(const AttractGroupId group_id);
+
+    void set_attraction_group_gain(const AttractGroupId group_id, const float new_gain);
+
+    void add_attraction_group(const AttractionGroup& group_info);
+
+    int num_attraction_groups();
+
+  private:
+    //Store each atom's attraction group assuming each atom is in at most one attraction group
+    //Atoms with no attraction group will have AttractGroupId::INVALID
+    vtr::vector<AtomBlockId, AttractGroupId> atom_attraction_group;
+
+    //Store atoms and gain value that belong to each attraction group
+    vtr::vector<AttractGroupId, AttractionGroup> attraction_groups;
+};
+
+inline AttractGroupId AttractionInfo::get_atom_attraction_group(const AtomBlockId atom_id) {
+    return atom_attraction_group[atom_id];
+}
+
+inline void AttractionInfo::set_atom_attraction_group(const AtomBlockId atom_id, const AttractGroupId group_id) {
+    atom_attraction_group[atom_id] = group_id;
+    attraction_groups[group_id].group_atoms.push_back(atom_id);
+}
+
+inline int AttractionInfo::num_attraction_groups() {
+    return attraction_groups.size();
+}
+
+inline float AttractionInfo::get_attraction_group_gain(const AttractGroupId group_id) {
+    return attraction_groups[group_id].gain;
+}
+
+inline void AttractionInfo::set_attraction_group_gain(const AttractGroupId group_id, const float new_gain) {
+    attraction_groups[group_id].gain = new_gain;
+}
+
+#endif /* VPR_SRC_PACK_ATTRACTION_GROUPS_H_ */