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AlexandreSingerAlexandreSinger
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[AP][PartialLegalizer] Added Bi-Partitioning Spreader
Bi-partitioning spreading is a technique where minimum spanning windows are formed around overfilled regions of the device such that the capacity of the bins within the window is larger than the utilization of the bins within the window. These windows are then successively partitioned, moving the blocks to the different partitions, until the window is small enough. Due to its divide and conquer nature, this algorithm tends to be very fast. Created a basic version of this algorithm which does not take into account the different types of blocks being spread. It worked suprisingly well, giving better QoR and runtime than the original spreader that I decided to merge this in immediately. In the future, will add these features. Kept the old spreader in as a separate Global Placer as it may be interesting to compare since the old multi-commodity flow-based approach should, in theory, do a better job spreading (at the expense of runtime). This old spreader may also be interesting to add into other stages of the flow. Added tests to keep this spreader from regressing.
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‎doc/src/vpr/command_line_usage.rst

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@@ -1188,6 +1188,16 @@ Analytical Placement is generally split into three stages:
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Analytical Placement is experimental and under active development.
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.. option:: --ap_global_placer {quadratic-bipartitioning-lookahead | quadratic-flowbased-lookahead}
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Controls which Global Placer to use in the AP Flow.
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* ``quadratic-bipartitioning-lookahead`` Use a Global Placer which uses a quadratic solver and a bi-partitioning lookahead legalizer. Anchor points are used to spread the solved solution to the legalized solution.
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* ``quadratic-flowbased-lookahead`` Use a Global Placer which uses a quadratic solver and a multi-commodity-flow-based lookahead legalizer. Anchor points are used to spread the solved solution to the legalized solution.
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**Default:** ``quadratic-bipartitioning-lookahead``
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.. option:: --ap_full_legalizer {naive | appack}
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Controls which Full Legalizer to use in the AP Flow.
@@ -1208,6 +1218,23 @@ Analytical Placement is generally split into three stages:
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**Default:** ``annealer``
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.. option:: --ap_verbosity <int>
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Controls the verbosity of the AP flow output.
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Larger values produce more detailed output, which may be useful for
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debugging the algorithms in the AP flow.
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* ``1 <= verbosity < 10`` Print standard, stage-level messages. This will
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print messages at the GP, FL, or DP level.
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* ``10 <= verbosity < 20`` Print more detailed messages of what is happening
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within stages. For example, show high-level information on the legalization
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iterations within the Global Placer.
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* ``20 <= verbosity`` Print very detailed messages on intra-stage algorithms.
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**Default:** ``1``
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.. _router_options:
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‎libs/libvtrutil/src/vtr_geometry.h

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@@ -180,6 +180,9 @@ class Rect {
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///@brief Returns true if other is contained within the rectangle (including all edges)
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bool contains(const Rect<T>& other) const;
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///@brief Returns true if other strictly overlaps this rectangle (two rectangles that only share an edge do not overlap)
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bool strictly_overlaps(const Rect<T>& other) const;
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/**
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* @brief Checks whether the rectangle is empty
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*

‎libs/libvtrutil/src/vtr_geometry.tpp

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@@ -187,6 +187,12 @@ bool Rect<T>::contains(const Rect<T>& other) const {
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&& other.ymin() >= ymin() && other.ymax() <= ymax();
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}
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template<class T>
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bool Rect<T>::strictly_overlaps(const Rect<T>& other) const {
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return xmin() < other.xmax() && xmax() > other.xmin()
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&& ymax() > other.ymin() && ymin() < other.ymax();
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}
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template<class T>
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bool Rect<T>::empty() const {
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return xmax() <= xmin() || ymax() <= ymin();

‎vpr/src/analytical_place/analytical_placement_flow.cpp

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@@ -114,7 +114,11 @@ static void convert_flat_to_partial_placement(const FlatPlacementInfo& flat_plac
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* @brief If a flat placement is provided, skips the Global Placer and
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* converts it to a partial placement. Otherwise, runs the Global Placer.
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*/
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static PartialPlacement run_global_placer(const AtomNetlist& atom_nlist, const APNetlist& ap_netlist, const Prepacker& prepacker, const DeviceContext& device_ctx) {
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static PartialPlacement run_global_placer(const t_ap_opts& ap_opts,
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const AtomNetlist& atom_nlist,
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const APNetlist& ap_netlist,
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const Prepacker& prepacker,
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const DeviceContext& device_ctx) {
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if (g_vpr_ctx.atom().flat_placement_info().valid) {
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VTR_LOG("Flat Placement is provided in the AP flow, skipping the Global Placement.\n");
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PartialPlacement p_placement(ap_netlist);
@@ -125,13 +129,14 @@ static PartialPlacement run_global_placer(const AtomNetlist& atom_nlist, const A
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return p_placement;
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} else {
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// Run the Global Placer
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std::unique_ptr<GlobalPlacer> global_placer = make_global_placer(e_global_placer::SimPL,
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std::unique_ptr<GlobalPlacer> global_placer = make_global_placer(ap_opts.global_placer_type,
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ap_netlist,
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prepacker,
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atom_nlist,
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device_ctx.grid,
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device_ctx.logical_block_types,
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device_ctx.physical_tile_types);
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device_ctx.physical_tile_types,
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ap_opts.log_verbosity);
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return global_placer->place();
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}
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}
@@ -156,7 +161,9 @@ void run_analytical_placement_flow(t_vpr_setup& vpr_setup) {
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print_ap_netlist_stats(ap_netlist);
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// Run the Global Placer.
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PartialPlacement p_placement = run_global_placer(atom_nlist,
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const t_ap_opts& ap_opts = vpr_setup.APOpts;
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PartialPlacement p_placement = run_global_placer(ap_opts,
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atom_nlist,
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ap_netlist,
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prepacker,
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device_ctx);
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device_ctx.grid.get_num_layers()));
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// Run the Full Legalizer.
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const t_ap_opts& ap_opts = vpr_setup.APOpts;
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std::unique_ptr<FullLegalizer> full_legalizer = make_full_legalizer(ap_opts.full_legalizer_type,
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ap_netlist,
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atom_nlist,

‎vpr/src/analytical_place/ap_flow_enums.h

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#pragma once
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/**
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* @brief The type of a Global Placer.
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*
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* The Analytical Placement flow may implement different Global Placers. This
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* enum can select between these different Global Placers.
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*/
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enum class e_ap_global_placer {
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// Global placers based on the the SimPL paper.
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SimPL_BiParitioning, ///< Global Placer based on the SimPL technique to Global Placement. Uses a quadratic solver and a bi-partitioning Partial Legalizer.
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SimPL_FlowBased ///< Global Placer based on the SimPL technique to Global Placement. Uses a quadratic solver and a multi-commodity-flow-baed Partial Legalizer.
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};
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/**
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* @brief The type of a Full Legalizer.
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*

‎vpr/src/analytical_place/global_placer.cpp

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#include <memory>
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#include <vector>
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#include "analytical_solver.h"
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#include "ap_flow_enums.h"
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#include "ap_netlist.h"
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#include "atom_netlist.h"
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#include "device_grid.h"
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#include "vtr_log.h"
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#include "vtr_time.h"
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std::unique_ptr<GlobalPlacer> make_global_placer(e_global_placer placer_type,
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std::unique_ptr<GlobalPlacer> make_global_placer(e_ap_global_placer placer_type,
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const APNetlist& ap_netlist,
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const Prepacker& prepacker,
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const AtomNetlist& atom_netlist,
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const DeviceGrid& device_grid,
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const std::vector<t_logical_block_type>& logical_block_types,
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const std::vector<t_physical_tile_type>& physical_tile_types) {
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const std::vector<t_physical_tile_type>& physical_tile_types,
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int log_verbosity) {
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// Based on the placer type passed in, build the global placer.
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switch (placer_type) {
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case e_global_placer::SimPL:
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return std::make_unique<SimPLGlobalPlacer>(ap_netlist,
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case e_ap_global_placer::SimPL_BiParitioning:
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return std::make_unique<SimPLGlobalPlacer>(e_partial_legalizer::BI_PARTITIONING,
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ap_netlist,
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prepacker,
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atom_netlist,
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device_grid,
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logical_block_types,
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physical_tile_types);
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physical_tile_types,
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log_verbosity);
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case e_ap_global_placer::SimPL_FlowBased:
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return std::make_unique<SimPLGlobalPlacer>(e_partial_legalizer::FLOW_BASED,
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ap_netlist,
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prepacker,
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atom_netlist,
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device_grid,
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logical_block_types,
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physical_tile_types,
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log_verbosity);
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default:
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VPR_FATAL_ERROR(VPR_ERROR_AP,
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"Unrecognized global placer type");
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}
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}
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SimPLGlobalPlacer::SimPLGlobalPlacer(const APNetlist& ap_netlist,
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SimPLGlobalPlacer::SimPLGlobalPlacer(e_partial_legalizer partial_legalizer_type,
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const APNetlist& ap_netlist,
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const Prepacker& prepacker,
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const AtomNetlist& atom_netlist,
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const DeviceGrid& device_grid,
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const std::vector<t_logical_block_type>& logical_block_types,
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const std::vector<t_physical_tile_type>& physical_tile_types)
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: GlobalPlacer(ap_netlist) {
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const std::vector<t_physical_tile_type>& physical_tile_types,
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int log_verbosity)
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: GlobalPlacer(ap_netlist, log_verbosity) {
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// This can be a long method. Good to time this to see how long it takes to
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// construct the global placer.
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vtr::ScopedStartFinishTimer global_placer_building_timer("Constructing Global Placer");
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physical_tile_types,
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log_verbosity_);
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// Build the partial legalizer
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partial_legalizer_ = make_partial_legalizer(e_partial_legalizer::FLOW_BASED,
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partial_legalizer_ = make_partial_legalizer(partial_legalizer_type,
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ap_netlist_,
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density_manager_);
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density_manager_,
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log_verbosity_);
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}
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/**

‎vpr/src/analytical_place/global_placer.h

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#pragma once
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#include <memory>
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#include "ap_flow_enums.h"
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#include "flat_placement_density_manager.h"
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#include "partial_legalizer.h"
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// Forward declarations
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class APNetlist;
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class Prepacker;
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struct PartialPlacement;
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/**
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* @brief Enumeration of all of the global placers currently implemented in VPR.
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*/
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enum class e_global_placer {
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SimPL // Global placer based on the SimPL paper.
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};
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/**
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* @brief The Global Placer base class
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*
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* @param log_verbosity The verbosity of log messages in the Global
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* Placer.
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*/
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GlobalPlacer(const APNetlist& ap_netlist, int log_verbosity = 1)
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GlobalPlacer(const APNetlist& ap_netlist, int log_verbosity)
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: ap_netlist_(ap_netlist),
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log_verbosity_(log_verbosity) {}
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/**
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* @brief A factory method which creates a Global Placer of the given type.
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*/
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std::unique_ptr<GlobalPlacer> make_global_placer(e_global_placer placer_type,
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std::unique_ptr<GlobalPlacer> make_global_placer(e_ap_global_placer placer_type,
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const APNetlist& ap_netlist,
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const Prepacker& prepacker,
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const AtomNetlist& atom_netlist,
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const DeviceGrid& device_grid,
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const std::vector<t_logical_block_type>& logical_block_types,
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const std::vector<t_physical_tile_type>& physical_tile_types);
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const std::vector<t_physical_tile_type>& physical_tile_types,
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int log_verbosity);
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/**
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* @brief A Global Placer based on the SimPL work for analytical ASIC placement.
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*
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* Constructs the solver and partial legalizer.
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*/
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SimPLGlobalPlacer(const APNetlist& ap_netlist,
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SimPLGlobalPlacer(e_partial_legalizer partial_legalizer_type,
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const APNetlist& ap_netlist,
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const Prepacker& prepacker,
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const AtomNetlist& atom_netlist,
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const DeviceGrid& device_grid,
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const std::vector<t_logical_block_type>& logical_block_types,
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const std::vector<t_physical_tile_type>& physical_tile_types);
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const std::vector<t_physical_tile_type>& physical_tile_types,
146+
int log_verbosity);
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/**
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* @brief Run a SimPL-like global placement algorithm

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