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Improving SA placer performance

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Signed-off-by: David Shah <davey1576@gmail.com>
This commit is contained in:
David Shah 2018-06-15 18:26:31 +02:00
parent 2d993d8ee9
commit 47566cf5e9
1 changed files with 50 additions and 21 deletions
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71
common/place.cc
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@ -36,6 +36,14 @@
#include "arch_place.h"
#include "log.h"
namespace std {
template <> struct hash<std::tuple<NEXTPNR_NAMESPACE_PREFIX BelType, int, int>> {
size_t operator()(const std::tuple<NEXTPNR_NAMESPACE_PREFIX BelType, int, int> &x) const noexcept {
return std::hash<int>()(get<0>(x)) + std::hash<int>()(get<1>(x)) + std::hash<int>()(get<2>(x));
}
};
};
NEXTPNR_NAMESPACE_BEGIN
void place_design(Design *design)
@ -143,7 +151,12 @@ static uint32_t xorshift32(rnd_state &rnd)
}
static float random_float_upto(rnd_state &rnd, float limit) {
return xorshift32(rnd) / (4294967295 / limit);
return xorshift32(rnd) / (4294967296 / limit);
}
static int random_int_between(rnd_state &rnd, int a, int b) {
return a + int(random_float_upto(rnd, b - a));
}
static void place_initial(Design *design, CellInfo *cell, rnd_state &rnd)
@ -184,6 +197,7 @@ struct SAState {
bool improved = false;
int n_move, n_accept;
int diameter = 35;
std::vector<std::vector<std::vector<std::vector<BelId>>>> fast_bels;
};
static float get_wirelength(Chip *chip, NetInfo *net) {
@ -212,8 +226,10 @@ static float get_wirelength(Chip *chip, NetInfo *net) {
}
static bool try_swap_position(Design *design, CellInfo *cell, BelId newBel, rnd_state &rnd, SAState &state) {
std::unordered_set<NetInfo *> update;
std::unordered_map<NetInfo *, float> new_lengths;
static std::unordered_set<NetInfo *> update;
static std::vector<std::pair<NetInfo *, float>> new_lengths;
new_lengths.clear();
update.clear();
Chip &chip = design->chip;
BelId oldBel = cell->bel;
IdString other = chip.getBelCell(newBel, true);
@ -258,7 +274,7 @@ static bool try_swap_position(Design *design, CellInfo *cell, BelId newBel, rnd_
new_wirelength -= state.wirelengths.at(net);
float net_new_wl = get_wirelength(&chip, net);
new_wirelength += net_new_wl;
new_lengths[net] = net_new_wl;
new_lengths.push_back(std::make_pair(net, net_new_wl));
}
delta = new_wirelength - state.best_wirelength;
state.n_move++;
@ -275,7 +291,7 @@ static bool try_swap_position(Design *design, CellInfo *cell, BelId newBel, rnd_
}
state.best_wirelength = new_wirelength;
for (auto new_wl : new_lengths)
state.wirelengths[new_wl.first] = new_wl.second;
state.wirelengths.at(new_wl.first) = new_wl.second;
return true;
swap_fail:
@ -288,28 +304,26 @@ swap_fail:
return false;
}
BelId random_bel_for_cell(Design *design, CellInfo *cell, SAState state, rnd_state &rnd)
BelId random_bel_for_cell(Design *design, CellInfo *cell, SAState& state, rnd_state &rnd)
{
BelId best_bel = BelId();
float best_score = std::numeric_limits<float>::infinity();
Chip &chip = design->chip;
BelType targetType = belTypeFromId(cell->type);
assert(int(targetType) < state.fast_bels.size());
float x = 0, y = 0;
chip.estimatePosition(cell->bel, x, y);
for (auto bel : chip.getBels()) {
if (chip.getBelType(bel) == targetType) {
float score = random_float_upto(rnd, 1.0);
float nx = 0, ny = 0;
chip.estimatePosition(bel, nx, ny);
if (std::abs(nx - x) > state.diameter || std::abs(ny - y) > state.diameter)
continue;
if (score <= best_score) {
best_score = score;
best_bel = bel;
}
}
while (true) {
int nx = random_int_between(rnd, std::max(int(x) - state.diameter, 0), int(x) + state.diameter + 1);
int ny = random_int_between(rnd, std::max(int(y) - state.diameter, 0), int(y) + state.diameter + 1);
if (nx >= state.fast_bels.at(int(targetType)).size())
continue;
if (ny >= state.fast_bels.at(int(targetType)).at(nx).size())
continue;
const auto &fb = state.fast_bels.at(int(targetType)).at(nx).at(ny);
if (fb.size() == 0)
continue;
return fb.at(random_int_between(rnd, 0, fb.size()));
}
return best_bel;
}
void place_design_heuristic(Design *design)
@ -347,6 +361,8 @@ void place_design_heuristic(Design *design)
rnd_state rnd;
rnd.state = 1;
std::vector<CellInfo *> autoplaced;
SAState state;
for (auto cell : design->cells) {
CellInfo *ci = cell.second;
if (ci->bel == BelId()) {
@ -356,7 +372,20 @@ void place_design_heuristic(Design *design)
}
log_info("placed %d/%d\n", placed_cells, total_cells);
}
SAState state;
for (auto bel : design->chip.getBels()) {
float x, y;
design->chip.estimatePosition(bel, x, y);
BelType type = design->chip.getBelType(bel);
if (state.fast_bels.size() < int(type)+1)
state.fast_bels.resize(int(type)+1);
if (state.fast_bels.at(int(type)).size() < int(x)+1)
state.fast_bels.at(int(type)).resize(int(x) + 1);
if (state.fast_bels.at(int(type)).at(int(x)).size() < int(y)+1)
state.fast_bels.at(int(type)).at(int(x)).resize(int(y) + 1);
state.fast_bels.at(int(type)).at(int(x)).at(int((y))).push_back(bel);
}
state.best_wirelength = 0;
for (auto net : design->nets) {
float wl = get_wirelength(&design->chip, net.second);