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nextpnr/common/parallel_refine.cc
gatecat df7e26c1aa clangformat 
Signed-off-by: gatecat <gatecat@ds0.me>
2022-03-09 17:12:59 +00:00

960 lines
36 KiB
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/*
* nextpnr -- Next Generation Place and Route
*
* Copyright (C) 2021-22 gatecat <gatecat@ds0.me>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
*/
#include "parallel_refine.h"
#include "log.h"
#if !defined(__wasm)
#include "fast_bels.h"
#include "scope_lock.h"
#include "timing.h"
#include <chrono>
#include <mutex>
#include <queue>
#include <shared_mutex>
#include <thread>
NEXTPNR_NAMESPACE_BEGIN
namespace {
struct Partition
{
int x0, y0, x1, y1;
std::vector<CellInfo *> cells;
Partition() = default;
explicit Partition(Context *ctx)
{
x0 = ctx->getGridDimX();
y0 = ctx->getGridDimY();
x1 = 0;
y1 = 0;
for (auto &cell : ctx->cells) {
Loc l = ctx->getBelLocation(cell.second->bel);
x0 = std::min(x0, l.x);
x1 = std::max(x1, l.x);
y0 = std::min(y0, l.y);
y1 = std::max(y1, l.y);
cells.push_back(cell.second.get());
}
}
void split(Context *ctx, bool yaxis, float pivot, Partition &l, Partition &r)
{
std::sort(cells.begin(), cells.end(), [&](CellInfo *a, CellInfo *b) {
Loc l0 = ctx->getBelLocation(a->bel), l1 = ctx->getBelLocation(b->bel);
return yaxis ? (l0.y < l1.y) : (l0.x < l1.x);
});
size_t pivot_point = size_t(cells.size() * pivot);
l.cells.clear();
r.cells.clear();
l.cells.reserve(pivot_point);
r.cells.reserve(cells.size() - pivot_point);
int pivot_coord = (pivot_point == 0) ? (yaxis ? y1 : x1)
: (yaxis ? ctx->getBelLocation(cells.at(pivot_point - 1)->bel).y
: ctx->getBelLocation(cells.at(pivot_point - 1)->bel).x);
for (size_t i = 0; i < cells.size(); i++) {
Loc loc = ctx->getBelLocation(cells.at(i)->bel);
((yaxis ? loc.y : loc.x) <= pivot_coord ? l.cells : r.cells).push_back(cells.at(i));
}
if (yaxis) {
l.x0 = r.x0 = x0;
l.x1 = r.x1 = x1;
l.y0 = y0;
l.y1 = pivot_coord;
r.y0 = (pivot_coord == y1) ? y1 : (pivot_coord + 1);
r.y1 = y1;
} else {
l.y0 = r.y0 = y0;
l.y1 = r.y1 = y1;
l.x0 = x0;
l.x1 = pivot_coord;
r.x0 = (pivot_coord == x1) ? x1 : (pivot_coord + 1);
r.x1 = x1;
}
}
};
typedef int64_t wirelen_t;
struct NetBB
{
// Actual bounding box
int x0 = 0, x1 = 0, y0 = 0, y1 = 0;
// Number of cells at each extremity
int nx0 = 0, nx1 = 0, ny0 = 0, ny1 = 0;
wirelen_t hpwl(const ParallelRefineCfg &cfg) const
{
return wirelen_t(cfg.hpwl_scale_x * (x1 - x0) + cfg.hpwl_scale_y * (y1 - y0));
}
static NetBB compute(const Context *ctx, const NetInfo *net, const dict<IdString, BelId> *cell2bel = nullptr)
{
NetBB result{};
if (!net->driver.cell)
return result;
auto bel_loc = [&](const CellInfo *cell) {
BelId bel = cell2bel ? cell2bel->at(cell->name) : cell->bel;
return ctx->getBelLocation(bel);
};
result.nx0 = result.nx1 = result.ny0 = result.ny1 = 1;
Loc drv_loc = bel_loc(net->driver.cell);
result.x0 = result.x1 = drv_loc.x;
result.y0 = result.y1 = drv_loc.y;
for (auto &usr : net->users) {
Loc l = bel_loc(usr.cell);
if (l.x == result.x0)
++result.nx0; // on the edge
else if (l.x < result.x0) {
result.x0 = l.x; // extends the edge
result.nx0 = 1;
}
if (l.x == result.x1)
++result.nx1; // on the edge
else if (l.x > result.x1) {
result.x1 = l.x; // extends the edge
result.nx1 = 1;
}
if (l.y == result.y0)
++result.ny0; // on the edge
else if (l.y < result.y0) {
result.y0 = l.y; // extends the edge
result.ny0 = 1;
}
if (l.y == result.y1)
++result.ny1; // on the edge
else if (l.y > result.y1) {
result.y1 = l.y; // extends the edge
result.ny1 = 1;
}
}
return result;
}
};
struct GlobalState
{
explicit GlobalState(Context *ctx, ParallelRefineCfg cfg) : ctx(ctx), cfg(cfg), bels(ctx, false, 64), tmg(ctx){};
Context *ctx;
ParallelRefineCfg cfg;
FastBels bels;
std::vector<NetInfo *> flat_nets; // flat array of all nets in the design for fast referencing by index
std::vector<NetBB> last_bounds;
std::vector<std::vector<double>> last_tmg_costs;
dict<IdString, NetBB> region_bounds;
TimingAnalyser tmg;
std::shared_timed_mutex archapi_mutex;
double temperature = 1e-7;
int radius = 3;
wirelen_t total_wirelen = 0;
double total_timing_cost = 0;
double get_timing_cost(const NetInfo *net, store_index<PortRef> user,
const dict<IdString, BelId> *cell2bel = nullptr)
{
if (!net->driver.cell)
return 0;
const auto &sink = net->users.at(user);
IdString driver_pin, sink_pin;
// Pick the first pin for a prediction; assume all will be similar enouhg
for (auto pin : ctx->getBelPinsForCellPin(net->driver.cell, net->driver.port)) {
driver_pin = pin;
break;
}
for (auto pin : ctx->getBelPinsForCellPin(sink.cell, sink.port)) {
sink_pin = pin;
break;
}
float crit = tmg.get_criticality(CellPortKey(sink));
BelId src_bel = cell2bel ? cell2bel->at(net->driver.cell->name) : net->driver.cell->bel;
BelId dst_bel = cell2bel ? cell2bel->at(sink.cell->name) : sink.cell->bel;
double delay = ctx->getDelayNS(ctx->predictDelay(src_bel, driver_pin, dst_bel, sink_pin));
return delay * std::pow(crit, cfg.crit_exp);
}
bool skip_net(const NetInfo *net) const
{
if (!net->driver.cell)
return true;
if (ctx->getBelGlobalBuf(net->driver.cell->bel))
return true;
return false;
}
bool timing_skip_net(const NetInfo *net) const
{
if (!net->driver.cell)
return true;
int cc;
auto cls = ctx->getPortTimingClass(net->driver.cell, net->driver.port, cc);
if (cls == TMG_IGNORE || cls == TMG_GEN_CLOCK)
return true;
return false;
}
// ....
};
struct ThreadState
{
Context *ctx; // Nextpnr context pointer
GlobalState &g; // Refinement engine state
int idx; // Index of the thread
DeterministicRNG rng; // Local RNG
// The cell partition that the thread works on
Partition p;
// Mapping from design-wide net index to thread-wide net index -- not all nets are in all partitions, so we can
// optimise
std::vector<int> thread_net_idx;
// List of nets inside the partition; and their committed bounding boxes & timing costs from the thread's
// perspective
std::vector<NetInfo *> thread_nets;
std::vector<NetBB> net_bounds;
std::vector<std::vector<double>> arc_tmg_cost;
std::vector<bool> ignored_nets, tmg_ignored_nets;
bool arch_state_dirty = false;
// Our local cell-bel map; that won't be affected by out-of-partition moves
dict<IdString, BelId> local_cell2bel;
// Data on an inflight move
dict<IdString, std::pair<BelId, BelId>> moved_cells; // cell -> (old; new)
// For cluster moves only
std::vector<std::pair<CellInfo *, Loc>> cell_rel;
// For incremental wirelength and delay updates
wirelen_t wirelen_delta = 0;
double timing_delta = 0;
// Total made and accepted moved
int n_move = 0, n_accept = 0;
enum BoundChange
{
NO_CHANGE,
CELL_MOVED_INWARDS,
CELL_MOVED_OUTWARDS,
FULL_RECOMPUTE
};
// Wirelen related are handled on a per-axis basis to reduce
struct AxisChanges
{
std::vector<int> bounds_changed_nets;
std::vector<BoundChange> already_bounds_changed;
};
std::array<AxisChanges, 2> axes;
std::vector<NetBB> new_net_bounds;
std::vector<std::vector<bool>> already_timing_changed;
std::vector<std::pair<int, store_index<PortRef>>> timing_changed_arcs;
std::vector<double> new_timing_costs;
ThreadState(Context *ctx, GlobalState &g, int idx) : ctx(ctx), g(g), idx(idx){};
void set_partition(const Partition &part)
{
p = part;
thread_nets.clear();
thread_net_idx.resize(g.flat_nets.size());
std::fill(thread_net_idx.begin(), thread_net_idx.end(), -1);
// Determine the set of nets that are within the thread; and therefore we care about
for (auto thread_cell : part.cells) {
for (auto &port : thread_cell->ports) {
if (!port.second.net)
continue;
int global_idx = port.second.net->udata;
auto &thread_idx = thread_net_idx.at(global_idx);
// Already added to the set
if (thread_idx != -1)
continue;
thread_idx = thread_nets.size();
thread_nets.push_back(port.second.net);
}
}
tmg_ignored_nets.clear();
ignored_nets.clear();
for (auto tn : thread_nets) {
ignored_nets.push_back(g.skip_net(tn));
tmg_ignored_nets.push_back(g.timing_skip_net(tn));
}
// Set up the original cell-bel map for all nets inside the thread
local_cell2bel.clear();
for (NetInfo *net : thread_nets) {
if (net->driver.cell)
local_cell2bel[net->driver.cell->name] = net->driver.cell->bel;
for (auto &usr : net->users)
local_cell2bel[usr.cell->name] = usr.cell->bel;
}
}
void setup_initial_state()
{
// Setup initial net bounding boxes and timing costs
net_bounds.clear();
arc_tmg_cost.clear();
for (auto tn : thread_nets) {
net_bounds.push_back(g.last_bounds.at(tn->udata));
arc_tmg_cost.push_back(g.last_tmg_costs.at(tn->udata));
}
new_net_bounds = net_bounds;
for (int j = 0; j < 2; j++) {
auto &a = axes.at(j);
a.already_bounds_changed.resize(net_bounds.size());
}
already_timing_changed.clear();
already_timing_changed.resize(net_bounds.size());
for (size_t i = 0; i < thread_nets.size(); i++)
already_timing_changed.at(i) = std::vector<bool>(thread_nets.at(i)->users.capacity());
}
bool bounds_check(BelId bel)
{
Loc l = ctx->getBelLocation(bel);
if (l.x < p.x0 || l.x > p.x1 || l.y < p.y0 || l.y > p.y1)
return false;
return true;
}
bool bind_move()
{
std::unique_lock<std::shared_timed_mutex> l(g.archapi_mutex);
for (auto &entry : moved_cells) {
ctx->unbindBel(entry.second.first);
}
bool success = true;
for (auto &entry : moved_cells) {
// Make sure targets are available before we bind them
if (!ctx->checkBelAvail(entry.second.second)) {
success = false;
break;
}
ctx->bindBel(entry.second.second, ctx->cells.at(entry.first).get(), STRENGTH_WEAK);
}
arch_state_dirty = true;
return success;
}
bool check_validity()
{
std::shared_lock<std::shared_timed_mutex> l(g.archapi_mutex);
bool result = true;
for (auto e : moved_cells) {
if (!ctx->isBelLocationValid(e.second.first)) {
// Have to check old; too; as unbinding a bel could make a placement illegal by virtue of no longer
// enabling dedicated routes to be used
result = false;
break;
}
if (!ctx->isBelLocationValid(e.second.second)) {
result = false;
break;
}
}
return result;
}
void revert_move()
{
if (arch_state_dirty) {
// If changes to the arch state were made, revert them by restoring original cell bindings
std::unique_lock<std::shared_timed_mutex> l(g.archapi_mutex);
for (auto &entry : moved_cells) {
BelId curr_bound = ctx->cells.at(entry.first)->bel;
if (curr_bound != BelId())
ctx->unbindBel(curr_bound);
}
for (auto &entry : moved_cells) {
ctx->bindBel(entry.second.first, ctx->cells.at(entry.first).get(), STRENGTH_WEAK);
}
arch_state_dirty = false;
}
for (auto &entry : moved_cells)
local_cell2bel[entry.first] = entry.second.first;
}
void commit_move()
{
arch_state_dirty = false;
for (auto &axis : axes) {
for (auto bc : axis.bounds_changed_nets) {
// Commit updated net bounds
net_bounds.at(bc) = new_net_bounds.at(bc);
}
}
if (g.cfg.timing_driven) {
NPNR_ASSERT(timing_changed_arcs.size() == new_timing_costs.size());
for (size_t i = 0; i < timing_changed_arcs.size(); i++) {
auto arc = timing_changed_arcs.at(i);
arc_tmg_cost.at(arc.first).at(arc.second.idx()) = new_timing_costs.at(i);
}
}
}
void compute_changes_for_cell(CellInfo *cell, BelId old_bel, BelId new_bel)
{
Loc new_loc = ctx->getBelLocation(new_bel);
Loc old_loc = ctx->getBelLocation(old_bel);
for (const auto &port : cell->ports) {
NetInfo *pn = port.second.net;
if (!pn)
continue;
int idx = thread_net_idx.at(pn->udata);
if (ignored_nets.at(idx))
continue;
NetBB &new_bounds = new_net_bounds.at(idx);
// For the x-axis (i=0) and y-axis (i=1)
for (int i = 0; i < 2; i++) {
auto &axis = axes.at(i);
// New and old on this axis
int new_pos = i ? new_loc.y : new_loc.x, old_pos = i ? old_loc.y : old_loc.x;
// References to updated bounding box entries
auto &b0 = i ? new_bounds.y0 : new_bounds.x0;
auto &n0 = i ? new_bounds.ny0 : new_bounds.nx0;
auto &b1 = i ? new_bounds.y1 : new_bounds.x1;
auto &n1 = i ? new_bounds.ny1 : new_bounds.nx1;
auto &change = axis.already_bounds_changed.at(idx);
// Lower bound
if (new_pos < b0) {
// Further out than current lower bound
b0 = new_pos;
n0 = 1;
if (change == NO_CHANGE) {
change = CELL_MOVED_OUTWARDS;
axis.bounds_changed_nets.push_back(idx);
}
} else if (new_pos == b0 && old_pos > b0) {
// Moved from inside into current bound
++n0;
if (change == NO_CHANGE) {
change = CELL_MOVED_OUTWARDS;
axis.bounds_changed_nets.push_back(idx);
}
} else if (old_pos == b0 && new_pos > b0) {
// Moved from current bound to inside
if (change == NO_CHANGE)
axis.bounds_changed_nets.push_back(idx);
if (n0 == 1) {
// Was the last cell on the bound; have to do a full recompute
change = FULL_RECOMPUTE;
} else {
--n0;
if (change == NO_CHANGE)
change = CELL_MOVED_INWARDS;
}
}
// Upper bound
if (new_pos > b1) {
// Further out than current upper bound
b1 = new_pos;
n1 = new_pos;
if (change == NO_CHANGE) {
change = CELL_MOVED_OUTWARDS;
axis.bounds_changed_nets.push_back(idx);
}
} else if (new_pos == b1 && old_pos < b1) {
// Moved onto current bound
++n1;
if (change == NO_CHANGE) {
change = CELL_MOVED_OUTWARDS;
axis.bounds_changed_nets.push_back(idx);
}
} else if (old_pos == b1 && new_pos < b1) {
// Moved from current bound to inside
if (change == NO_CHANGE)
axis.bounds_changed_nets.push_back(idx);
if (n1 == 1) {
// Was the last cell on the bound; have to do a full recompute
change = FULL_RECOMPUTE;
} else {
--n1;
if (change == NO_CHANGE)
change = CELL_MOVED_INWARDS;
}
}
}
// Timing updates if timing driven
if (g.cfg.timing_driven && !tmg_ignored_nets.at(idx)) {
if (port.second.type == PORT_OUT) {
int cc;
TimingPortClass cls = ctx->getPortTimingClass(cell, port.first, cc);
if (cls != TMG_IGNORE) {
for (auto usr : pn->users.enumerate())
if (!already_timing_changed.at(idx).at(usr.index.idx())) {
timing_changed_arcs.emplace_back(std::make_pair(idx, usr.index));
already_timing_changed.at(idx).at(usr.index.idx()) = true;
}
}
} else {
auto usr = port.second.user_idx;
if (!already_timing_changed.at(idx).at(usr.idx())) {
timing_changed_arcs.emplace_back(std::make_pair(idx, usr));
already_timing_changed.at(idx).at(usr.idx()) = true;
}
}
}
}
}
void compute_total_change()
{
auto &xa = axes.at(0), &ya = axes.at(1);
for (auto &bc : xa.bounds_changed_nets)
if (xa.already_bounds_changed.at(bc) == FULL_RECOMPUTE)
new_net_bounds.at(bc) = NetBB::compute(ctx, thread_nets.at(bc), &local_cell2bel);
for (auto &bc : ya.bounds_changed_nets)
if (xa.already_bounds_changed.at(bc) != FULL_RECOMPUTE &&
ya.already_bounds_changed.at(bc) == FULL_RECOMPUTE)
new_net_bounds.at(bc) = NetBB::compute(ctx, thread_nets.at(bc), &local_cell2bel);
for (auto &bc : xa.bounds_changed_nets)
wirelen_delta += (new_net_bounds.at(bc).hpwl(g.cfg) - net_bounds.at(bc).hpwl(g.cfg));
for (auto &bc : ya.bounds_changed_nets)
if (xa.already_bounds_changed.at(bc) == NO_CHANGE)
wirelen_delta += (new_net_bounds.at(bc).hpwl(g.cfg) - net_bounds.at(bc).hpwl(g.cfg));
if (g.cfg.timing_driven) {
NPNR_ASSERT(new_timing_costs.empty());
for (auto arc : timing_changed_arcs) {
double new_cost = g.get_timing_cost(thread_nets.at(arc.first), arc.second, &local_cell2bel);
timing_delta += (new_cost - arc_tmg_cost.at(arc.first).at(arc.second.idx()));
new_timing_costs.push_back(new_cost);
}
}
}
void reset_move_state()
{
moved_cells.clear();
cell_rel.clear();
for (auto &axis : axes) {
for (auto bc : axis.bounds_changed_nets) {
new_net_bounds.at(bc) = net_bounds.at(bc);
axis.already_bounds_changed[bc] = NO_CHANGE;
}
axis.bounds_changed_nets.clear();
}
for (auto &arc : timing_changed_arcs) {
already_timing_changed.at(arc.first).at(arc.second.idx()) = false;
}
timing_changed_arcs.clear();
new_timing_costs.clear();
wirelen_delta = 0;
timing_delta = 0;
}
bool accept_move()
{
double delta = g.cfg.lambda * (timing_delta / std::max<double>(epsilon, g.total_timing_cost)) +
(1.0 - g.cfg.lambda) * (double(wirelen_delta) / std::max<double>(epsilon, g.total_wirelen));
return delta < 0 ||
(g.temperature > 1e-8 && (rng.rng() / float(0x3fffffff)) <= std::exp(-delta / g.temperature));
}
bool add_to_move(CellInfo *cell, BelId old_bel, BelId new_bel)
{
if (!bounds_check(old_bel) || !bounds_check(new_bel))
return false;
if (!ctx->isValidBelForCellType(cell->type, new_bel))
return false;
NPNR_ASSERT(!moved_cells.count(cell->name));
moved_cells[cell->name] = std::make_pair(old_bel, new_bel);
local_cell2bel[cell->name] = new_bel;
compute_changes_for_cell(cell, old_bel, new_bel);
return true;
}
static constexpr double epsilon = 1e-20;
bool single_cell_swap(CellInfo *cell, BelId new_bel)
{
NPNR_ASSERT(moved_cells.empty());
BelId old_bel = cell->bel;
CellInfo *bound = ctx->getBoundBelCell(new_bel);
if (bound && (bound->belStrength > STRENGTH_STRONG || bound->cluster != ClusterId()))
return false;
if (!add_to_move(cell, old_bel, new_bel))
goto fail;
if (bound && !add_to_move(bound, new_bel, old_bel))
goto fail;
compute_total_change();
// SA acceptance criteria
if (!accept_move()) {
// SA fail
goto fail;
}
// Check validity rules
if (!bind_move())
goto fail;
if (!check_validity())
goto fail;
// Accepted!
commit_move();
reset_move_state();
return true;
fail:
revert_move();
reset_move_state();
return false;
}
bool chain_swap(CellInfo *root_cell, BelId new_root_bel)
{
NPNR_ASSERT(moved_cells.empty());
std::queue<std::pair<ClusterId, BelId>> displaced_clusters;
pool<BelId> used_bels;
displaced_clusters.emplace(root_cell->cluster, new_root_bel);
while (!displaced_clusters.empty()) {
std::vector<std::pair<CellInfo *, BelId>> dest_bels;
auto cursor = displaced_clusters.front();
displaced_clusters.pop();
if (!ctx->getClusterPlacement(cursor.first, cursor.second, dest_bels))
goto fail;
for (const auto &db : dest_bels) {
BelId old_bel = db.first->bel;
if (moved_cells.count(db.first->name))
goto fail;
if (!add_to_move(db.first, old_bel, db.second))
goto fail;
if (used_bels.count(db.second))
goto fail;
used_bels.insert(db.second);
CellInfo *bound = ctx->getBoundBelCell(db.second);
if (bound) {
if (moved_cells.count(bound->name)) {
// Don't move a cell multiple times in the same go
goto fail;
} else if (bound->belStrength > STRENGTH_STRONG) {
goto fail;
} else if (bound->cluster != ClusterId()) {
// Displace the entire cluster
Loc old_loc = ctx->getBelLocation(old_bel);
Loc bound_loc = ctx->getBelLocation(bound->bel);
Loc root_loc = ctx->getBelLocation(ctx->getClusterRootCell(bound->cluster)->bel);
BelId new_root = ctx->getBelByLocation(Loc(old_loc.x + (root_loc.x - bound_loc.x),
old_loc.y + (root_loc.y - bound_loc.y),
old_loc.z + (root_loc.z - bound_loc.z)));
if (new_root == BelId())
goto fail;
displaced_clusters.emplace(bound->cluster, new_root);
} else {
// Single cell swap
if (used_bels.count(old_bel))
goto fail;
used_bels.insert(old_bel);
if (!add_to_move(bound, bound->bel, old_bel))
goto fail;
}
} else if (!ctx->checkBelAvail(db.second)) {
goto fail;
}
}
}
compute_total_change();
// SA acceptance criteria
if (!accept_move()) {
// SA fail
goto fail;
}
// Check validity rules
if (!bind_move())
goto fail;
if (!check_validity())
goto fail;
// Accepted!
commit_move();
reset_move_state();
return true;
fail:
revert_move();
reset_move_state();
return false;
}
BelId random_bel_for_cell(CellInfo *cell, int force_z = -1)
{
IdString targetType = cell->type;
Loc curr_loc = ctx->getBelLocation(cell->bel);
int count = 0;
int dx = g.radius, dy = g.radius;
if (cell->region != nullptr && cell->region->constr_bels) {
dx = std::min(g.cfg.hpwl_scale_x * g.radius,
(g.region_bounds[cell->region->name].x1 - g.region_bounds[cell->region->name].x0) + 1);
dy = std::min(g.cfg.hpwl_scale_y * g.radius,
(g.region_bounds[cell->region->name].y1 - g.region_bounds[cell->region->name].y0) + 1);
// Clamp location to within bounds
curr_loc.x = std::max(g.region_bounds[cell->region->name].x0, curr_loc.x);
curr_loc.x = std::min(g.region_bounds[cell->region->name].x1, curr_loc.x);
curr_loc.y = std::max(g.region_bounds[cell->region->name].y0, curr_loc.y);
curr_loc.y = std::min(g.region_bounds[cell->region->name].y1, curr_loc.y);
}
FastBels::FastBelsData *bel_data;
auto type_cnt = g.bels.getBelsForCellType(targetType, &bel_data);
while (true) {
int nx = rng.rng(2 * dx + 1) + std::max(curr_loc.x - dx, 0);
int ny = rng.rng(2 * dy + 1) + std::max(curr_loc.y - dy, 0);
if (type_cnt < 64)
nx = ny = 0;
if (nx >= int(bel_data->size()))
continue;
if (ny >= int(bel_data->at(nx).size()))
continue;
const auto &fb = bel_data->at(nx).at(ny);
if (fb.size() == 0)
continue;
BelId bel = fb.at(rng.rng(int(fb.size())));
if (!bounds_check(bel))
continue;
if (force_z != -1) {
Loc loc = ctx->getBelLocation(bel);
if (loc.z != force_z)
continue;
}
if (!cell->testRegion(bel))
continue;
count++;
return bel;
}
}
void run_iter()
{
setup_initial_state();
n_accept = 0;
n_move = 0;
for (int m = 0; m < g.cfg.inner_iters; m++) {
for (auto cell : p.cells) {
if (cell->belStrength > STRENGTH_STRONG)
continue;
if (cell->cluster != ClusterId()) {
if (cell != ctx->getClusterRootCell(cell->cluster))
continue; // only move cluster root
Loc old_loc = ctx->getBelLocation(cell->bel);
BelId new_root = random_bel_for_cell(cell, old_loc.z);
if (new_root == BelId() || new_root == cell->bel)
continue;
++n_move;
if (chain_swap(cell, new_root))
++n_accept;
} else {
BelId new_bel = random_bel_for_cell(cell);
if (new_bel == BelId() || new_bel == cell->bel)
continue;
++n_move;
if (single_cell_swap(cell, new_bel))
++n_accept;
}
}
}
}
};
struct ParallelRefine
{
Context *ctx;
GlobalState g;
std::vector<ThreadState> t;
ParallelRefine(Context *ctx, ParallelRefineCfg cfg) : ctx(ctx), g(ctx, cfg)
{
g.flat_nets.reserve(ctx->nets.size());
for (auto &net : ctx->nets) {
net.second->udata = g.flat_nets.size();
g.flat_nets.push_back(net.second.get());
}
// Setup per thread context
for (int i = 0; i < cfg.threads; i++) {
t.emplace_back(ctx, g, i);
}
// Setup region bounds
for (auto &region : ctx->region) {
Region *r = region.second.get();
NetBB bb;
if (r->constr_bels) {
bb.x0 = std::numeric_limits<int>::max();
bb.x1 = std::numeric_limits<int>::min();
bb.y0 = std::numeric_limits<int>::max();
bb.y1 = std::numeric_limits<int>::min();
for (auto bel : r->bels) {
Loc loc = ctx->getBelLocation(bel);
bb.x0 = std::min(bb.x0, loc.x);
bb.x1 = std::max(bb.x1, loc.x);
bb.y0 = std::min(bb.y0, loc.y);
bb.y1 = std::max(bb.y1, loc.y);
}
} else {
bb.x0 = 0;
bb.y0 = 0;
bb.x1 = ctx->getGridDimX();
bb.y1 = ctx->getGridDimY();
}
g.region_bounds[r->name] = bb;
}
// Setup fast bels map
pool<IdString> cell_types_in_use;
for (auto &cell : ctx->cells) {
IdString cell_type = cell.second->type;
cell_types_in_use.insert(cell_type);
}
for (auto cell_type : cell_types_in_use) {
g.bels.addCellType(cell_type);
}
};
std::vector<Partition> parts;
void do_partition()
{
parts.clear();
parts.emplace_back(ctx);
bool yaxis = false;
while (parts.size() < t.size()) {
std::vector<Partition> next(parts.size() * 2);
for (size_t i = 0; i < parts.size(); i++) {
// Randomly permute pivot every iteration so we get different thread boundaries
const float delta = 0.1;
float pivot = (0.5 - (delta / 2)) + (delta / 2) * (ctx->rng(10000) / 10000.0f);
parts.at(i).split(ctx, yaxis, pivot, next.at(i * 2), next.at(i * 2 + 1));
}
std::swap(parts, next);
yaxis = !yaxis;
}
NPNR_ASSERT(parts.size() == t.size());
// TODO: thread pool to make this worthwhile...
std::vector<std::thread> workers;
for (size_t i = 0; i < t.size(); i++) {
workers.emplace_back([i, this]() { t.at(i).set_partition(parts.at(i)); });
}
for (auto &w : workers)
w.join();
}
void update_global_costs()
{
g.last_bounds.resize(g.flat_nets.size());
g.last_tmg_costs.resize(g.flat_nets.size());
g.total_wirelen = 0;
g.total_timing_cost = 0;
for (size_t i = 0; i < g.flat_nets.size(); i++) {
NetInfo *ni = g.flat_nets.at(i);
if (g.skip_net(ni))
continue;
g.last_bounds.at(i) = NetBB::compute(ctx, ni);
g.total_wirelen += g.last_bounds.at(i).hpwl(g.cfg);
if (!g.timing_skip_net(ni)) {
auto &tc = g.last_tmg_costs.at(i);
tc.resize(ni->users.capacity());
for (auto usr : ni->users.enumerate()) {
tc.at(usr.index.idx()) = g.get_timing_cost(ni, usr.index);
g.total_timing_cost += tc.at(usr.index.idx());
}
}
}
}
void run()
{
ScopeLock<Context> lock(ctx);
auto refine_start = std::chrono::high_resolution_clock::now();
g.tmg.setup_only = true;
g.tmg.setup();
do_partition();
log_info("Running parallel refinement with %d threads.\n", int(t.size()));
int iter = 1;
bool done = false;
update_global_costs();
double avg_wirelen = g.total_wirelen;
wirelen_t min_wirelen = g.total_wirelen;
while (true) {
if (iter > 1) {
if (g.total_wirelen >= min_wirelen) {
done = true;
} else if (g.total_wirelen < min_wirelen) {
min_wirelen = g.total_wirelen;
}
int n_accept = 0, n_move = 0;
for (auto &t_data : t) {
n_accept += t_data.n_accept;
n_move += t_data.n_move;
}
double r_accept = n_accept / double(n_move);
if (g.total_wirelen < (0.95 * avg_wirelen) && g.total_wirelen > 0) {
avg_wirelen = 0.8 * avg_wirelen + 0.2 * g.total_wirelen;
} else {
if (r_accept > 0.15 && g.radius > 1) {
g.temperature *= 0.95;
} else {
g.temperature *= 0.8;
}
}
if ((iter % 10) == 0 && g.radius > 1)
--g.radius;
}
if ((iter == 1) || ((iter % 5) == 0) || done)
log_info(" at iteration #%d: temp = %f, timing cost = "
"%.0f, wirelen = %.0f\n",
iter, g.temperature, double(g.total_timing_cost), double(g.total_wirelen));
if (done)
break;
do_partition();
std::vector<std::thread> workers;
workers.reserve(t.size());
for (int j = 0; j < int(t.size()); j++)
workers.emplace_back([this, j]() { t.at(j).run_iter(); });
for (auto &w : workers)
w.join();
g.tmg.run();
update_global_costs();
iter++;
ctx->yield();
}
auto refine_end = std::chrono::high_resolution_clock::now();
log_info("Placement refine time %.02fs\n", std::chrono::duration<float>(refine_end - refine_start).count());
}
};
} // namespace
ParallelRefineCfg::ParallelRefineCfg(Context *ctx)
{
timing_driven = ctx->setting<bool>("timing_driven");
threads = ctx->setting<int>("threads", 8);
// snap to nearest power of two; and minimum thread size
int actual_threads = 1;
while ((actual_threads * 2) <= threads && (int(ctx->cells.size()) / (actual_threads * 2)) >= min_thread_size)
actual_threads *= 2;
threads = actual_threads;
hpwl_scale_x = 1;
hpwl_scale_y = 1;
}
bool parallel_refine(Context *ctx, ParallelRefineCfg cfg)
{
// TODO
ParallelRefine refine(ctx, cfg);
refine.run();
timing_analysis(ctx);
return true;
}
NEXTPNR_NAMESPACE_END
#else /* !defined(__wasm) */
NEXTPNR_NAMESPACE_BEGIN
bool parallel_refine(Context *ctx, ParallelRefineCfg cfg) { log_abort(); }
NEXTPNR_NAMESPACE_END
#endif
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