aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
Diffstat
-rw-r--r--common/placer1.cc14
-rw-r--r--common/router1.cc1
-rw-r--r--common/timing.cc123
-rw-r--r--common/timing.h2
4 files changed, 138 insertions, 2 deletions
diff --git a/common/placer1.cc b/common/placer1.cc
index 74a11040..be20c072 100644
--- a/common/placer1.cc
+++ b/common/placer1.cc
@@ -145,6 +145,7 @@ class SAPlacer
}
int n_no_progress = 0;
+ wirelen_t min_metric = curr_metric;
double avg_metric = curr_metric;
temp = 10000;
@@ -169,6 +170,12 @@ class SAPlacer
try_swap_position(cell, try_bel);
}
}
+
+ if (curr_metric < min_metric) {
+ min_metric = curr_metric;
+ improved = true;
+ }
+
// Heuristic to improve placement on the 8k
if (improved)
n_no_progress = 0;
@@ -222,6 +229,9 @@ class SAPlacer
ctx->shuffle(autoplaced);
assign_budget(ctx);
}
+ else {
+ update_budget(ctx);
+ }
// Recalculate total metric entirely to avoid rounding errors
// accumulating over time
@@ -365,8 +375,8 @@ class SAPlacer
// SA acceptance criterea
if (delta < 0 || (temp > 1e-6 && (ctx->rng() / float(0x3fffffff)) <= std::exp(-delta / temp))) {
n_accept++;
- if (delta < 2)
- improved = true;
+ //if (delta < 2)
+ // improved = true;
} else {
if (other != IdString())
ctx->unbindBel(oldBel);
diff --git a/common/router1.cc b/common/router1.cc
index 1ea50448..86fb1a44 100644
--- a/common/router1.cc
+++ b/common/router1.cc
@@ -499,6 +499,7 @@ struct RouteJob
};
};
+
void addFullNetRouteJob(Context *ctx, IdString net_name,
std::unordered_map<IdString, std::vector<bool>> &cache,
std::priority_queue<RouteJob, std::vector<RouteJob>, RouteJob::Greater> &queue)
diff --git a/common/timing.cc b/common/timing.cc
index 3a48935f..5f744621 100644
--- a/common/timing.cc
+++ b/common/timing.cc
@@ -22,6 +22,7 @@
#include <unordered_map>
#include <utility>
#include "log.h"
+#include "util.h"
NEXTPNR_NAMESPACE_BEGIN
@@ -114,4 +115,126 @@ void assign_budget(Context *ctx)
log_info("Checksum: 0x%08x\n", ctx->checksum());
}
+typedef std::unordered_map<const PortInfo*, delay_t> updates_t;
+typedef std::unordered_map<const PortInfo*, delay_t> delays_t;
+
+static delay_t follow_net_update(Context *ctx, NetInfo *net, int path_length, delay_t slack, const delays_t& delays, updates_t& updates);
+
+// Follow a path, returning budget to annotate
+static delay_t follow_user_port_update(Context *ctx, PortRef &user, int path_length, delay_t slack, const delays_t& delays, updates_t& updates)
+{
+ delay_t value;
+ if (ctx->getPortClock(user.cell, user.port) != IdString()) {
+ // At the end of a timing path (arguably, should check setup time
+ // here too)
+ value = slack / path_length;
+ } else {
+ // Default to the path ending here, if no further paths found
+ value = slack / path_length;
+ // Follow outputs of the user
+ for (auto& port : user.cell->ports) {
+ if (port.second.type == PORT_OUT) {
+ delay_t comb_delay;
+ // Look up delay through this path
+ bool is_path = ctx->getCellDelay(user.cell, user.port, port.first, comb_delay);
+ if (is_path) {
+ NetInfo *net = port.second.net;
+ if (net) {
+ delay_t path_budget = follow_net_update(ctx, net, path_length, slack - comb_delay, delays, updates);
+ value = std::min(value, path_budget);
+ }
+ }
+ }
+ }
+ }
+
+ auto ret = updates.emplace(&user.cell->ports.at(user.port), value);
+ if (!ret.second && value < ret.first->second) {
+ ret.first->second = value;
+ }
+ return value;
+}
+
+static delay_t follow_net_update(Context *ctx, NetInfo *net, int path_length, delay_t slack, const delays_t& delays,updates_t& updates)
+{
+ delay_t net_budget = slack / (path_length + 1);
+ for (auto& usr : net->users) {
+ net_budget = std::min(net_budget, follow_user_port_update(ctx, usr, path_length + 1, slack - get_or_default(delays, &usr.cell->ports.at(usr.port), 0.), delays, updates));
+ }
+ return net_budget;
+}
+
+void update_budget(Context *ctx)
+{
+ delays_t delays;
+ updates_t updates;
+
+ // Compute the delay for every pin on every net
+ for (auto &n : ctx->nets) {
+ auto net = n.second.get();
+
+ int driver_x, driver_y;
+ bool driver_gb;
+ CellInfo *driver_cell = net->driver.cell;
+ if (!driver_cell)
+ continue;
+ if (driver_cell->bel == BelId())
+ continue;
+ ctx->estimatePosition(driver_cell->bel, driver_x, driver_y, driver_gb);
+ WireId drv_wire = ctx->getWireBelPin(driver_cell->bel, ctx->portPinFromId(net->driver.port));
+ if (driver_gb)
+ continue;
+ for (auto& load : net->users) {
+ if (load.cell == nullptr)
+ continue;
+ CellInfo *load_cell = load.cell;
+ if (load_cell->bel == BelId())
+ continue;
+ WireId user_wire = ctx->getWireBelPin(load_cell->bel, ctx->portPinFromId(load.port));
+ delay_t raw_wl = ctx->estimateDelay(drv_wire, user_wire);
+ delays.emplace(&load_cell->ports.at(load.port), raw_wl);
+ }
+ }
+
+ // Go through all clocked drivers and distribute the available path slack evenly into every budget
+ for (auto &cell : ctx->cells) {
+ for (auto& port : cell.second->ports) {
+ if (port.second.type == PORT_OUT) {
+ IdString clock_domain = ctx->getPortClock(cell.second.get(), port.first);
+ if (clock_domain != IdString()) {
+ if (port.second.net)
+ follow_net_update(ctx, port.second.net, 0, delay_t(1.0e12 / ctx->target_freq) - get_or_default(delays, &port.second, 0.), delays, updates);
+ }
+ }
+ }
+ }
+
+ // Update the budgets
+ for (auto &net : ctx->nets) {
+ for (auto& user : net.second->users) {
+ auto pi = &user.cell->ports.at(user.port);
+ auto it = updates.find(pi);
+ if (it == updates.end()) continue;
+ user.budget = delays.at(pi) + it->second;
+
+ // HACK HACK HACK
+ if (net.second->driver.port == ctx->id("COUT"))
+ user.budget = 0;
+ // HACK HACK HACK
+
+ // Post-update check
+// if (user.budget < 0)
+// log_warning("port %s.%s, connected to net '%s', has negative "
+// "timing budget of %fns\n",
+// user.cell->name.c_str(ctx), user.port.c_str(ctx), net.first.c_str(ctx),
+// ctx->getDelayNS(user.budget));
+// if (ctx->verbose)
+// log_info("port %s.%s, connected to net '%s', has "
+// "timing budget of %fns\n",
+// user.cell->name.c_str(ctx), user.port.c_str(ctx), net.first.c_str(ctx),
+// ctx->getDelayNS(user.budget));
+ }
+ }
+}
+
NEXTPNR_NAMESPACE_END
diff --git a/common/timing.h b/common/timing.h
index 025e4a76..b5574392 100644
--- a/common/timing.h
+++ b/common/timing.h
@@ -27,6 +27,8 @@ NEXTPNR_NAMESPACE_BEGIN
// Assign "budget" values for all user ports in the design
void assign_budget(Context *ctx);
+void update_budget(Context *ctx);
+
NEXTPNR_NAMESPACE_END
#endif
generated by cgit v1.2.3 (git 2.25.1) at 2025-05-28 12:09:01 +0000