Merge branch 'redist_slack' into 'redist_slack'

Redist slack

See merge request eddiehung/nextpnr!14

5 files changed, 32 insertions, 62 deletions

diff --git a/common/placer1.cc b/common/placer1.cc
index d0771e5c..c677a22a 100644
--- a/common/placer1.cc
+++ b/common/placer1.cc
@@ -237,7 +237,7 @@ class SAPlacer
                 ctx->shuffle(autoplaced);
                 assign_budget(ctx);
             } else {
-                update_budget(ctx);
+                assign_budget(ctx, true /* quiet */);
             }
 
             // Recalculate total metric entirely to avoid rounding errors
diff --git a/common/router1.cc b/common/router1.cc
index d1551363..e18f27fb 100644
--- a/common/router1.cc
+++ b/common/router1.cc
@@ -616,7 +616,7 @@ bool router1(Context *ctx)
             if (ctx->verbose || iterCnt == 1)
                 log_info("routing queue contains %d jobs.\n", int(jobQueue.size()));
 
-            update_budget(ctx);
+            assign_budget(ctx, true /* quiet */);
 
             bool printNets = ctx->verbose && (jobQueue.size() < 10);
 
diff --git a/common/timing.cc b/common/timing.cc
index 20cfd1b5..c6e2b037 100644
--- a/common/timing.cc
+++ b/common/timing.cc
@@ -28,8 +28,8 @@ NEXTPNR_NAMESPACE_BEGIN
 
 typedef std::list<const PortRef *> PortRefList;
 
-static delay_t follow_net(Context *ctx, NetInfo *net, int path_length, delay_t slack, bool update,
-                          delay_t &min_slack, PortRefList *current_path, PortRefList *crit_path);
+static delay_t follow_net(Context *ctx, NetInfo *net, int path_length, delay_t slack, bool update, delay_t &min_slack,
+                          PortRefList *current_path, PortRefList *crit_path);
 
 // Follow a path, returning budget to annotate
 static delay_t follow_user_port(Context *ctx, PortRef &user, int path_length, delay_t slack, bool update,
@@ -68,8 +68,8 @@ static delay_t follow_user_port(Context *ctx, PortRef &user, int path_length, de
     return value;
 }
 
-static delay_t follow_net(Context *ctx, NetInfo *net, int path_length, delay_t slack, bool update,
-                          delay_t &min_slack, PortRefList *current_path, PortRefList *crit_path)
+static delay_t follow_net(Context *ctx, NetInfo *net, int path_length, delay_t slack, bool update, delay_t &min_slack,
+                          PortRefList *current_path, PortRefList *crit_path)
 {
     delay_t net_budget = slack / (path_length + 1);
     for (unsigned i = 0; i < net->users.size(); ++i) {
@@ -83,11 +83,11 @@ static delay_t follow_net(Context *ctx, NetInfo *net, int path_length, delay_t s
             net_budget = budget;
             pl = std::max(1, path_length);
         }
-        net_budget = std::min(net_budget,
-                              follow_user_port(ctx, usr, pl, slack - ctx->getNetinfoRouteDelay(net, i),
-                                               update, min_slack, current_path, crit_path));
+        auto delay = ctx->getNetinfoRouteDelay(net, i);
+        net_budget = std::min(
+                net_budget, follow_user_port(ctx, usr, pl, slack - delay, update, min_slack, current_path, crit_path));
         if (update)
-            usr.budget = std::min(usr.budget, net_budget);
+            usr.budget = std::min(usr.budget, delay + net_budget);
         if (crit_path)
             current_path->pop_back();
     }
@@ -123,10 +123,13 @@ static delay_t walk_paths(Context *ctx, bool update, PortRefList *crit_path)
     return min_slack;
 }
 
-void assign_budget(Context *ctx)
+void assign_budget(Context *ctx, bool quiet)
 {
-    log_break();
-    log_info("Annotating ports with timing budgets\n");
+    if (!quiet) {
+        log_break();
+        log_info("Annotating ports with timing budgets\n");
+    }
+
     // Clear delays to a very high value first
     delay_t default_slack = delay_t(1.0e12 / ctx->target_freq);
     for (auto &net : ctx->nets) {
@@ -137,42 +140,7 @@ void assign_budget(Context *ctx)
 
     delay_t min_slack = walk_paths(ctx, true, nullptr);
 
-    for (auto &net : ctx->nets) {
-        for (auto &user : net.second->users) {
-            // Post-update check
-            if (ctx->user_freq && 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));
-        }
-    }
-
-    // If user has not specified a frequency, adjust the target frequency dynamically
-    // TODO(eddieh): Tune these factors
-    if (!ctx->user_freq) {
-        if (min_slack < 0)
-            ctx->target_freq = 1e12 / (default_slack - 0.95 * min_slack);
-        else
-            ctx->target_freq = 1e12 / (default_slack - 1.2 * min_slack);
-        if (ctx->verbose)
-            log_info("minimum slack for this assign = %d, target Fmax for next update = %.2f MHz\n", min_slack,
-                     ctx->target_freq / 1e6);
-    }
-
-    log_info("Checksum: 0x%08x\n", ctx->checksum());
-}
-
-void update_budget(Context *ctx)
-{
-    delay_t min_slack = walk_paths(ctx, true, nullptr);
-
-    if (ctx->verbose) {
+    if (!quiet || ctx->verbose) {
         for (auto &net : ctx->nets) {
             for (auto &user : net.second->users) {
                 // Post-update check
@@ -181,7 +149,7 @@ void update_budget(Context *ctx)
                                 "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));
-                else
+                else 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),
@@ -193,7 +161,6 @@ void update_budget(Context *ctx)
     // If user has not specified a frequency, adjust the target frequency dynamically
     // TODO(eddieh): Tune these factors
     if (!ctx->user_freq) {
-        delay_t default_slack = delay_t(1.0e12 / ctx->target_freq);
         if (min_slack < 0)
             ctx->target_freq = 1e12 / (default_slack - 0.95 * min_slack);
         else
@@ -202,6 +169,9 @@ void update_budget(Context *ctx)
             log_info("minimum slack for this assign = %d, target Fmax for next update = %.2f MHz\n", min_slack,
                      ctx->target_freq / 1e6);
     }
+
+    if (!quiet)
+        log_info("Checksum: 0x%08x\n", ctx->checksum());
 }
 
 delay_t timing_analysis(Context *ctx, bool print_fmax, bool print_path)
@@ -224,8 +194,10 @@ delay_t timing_analysis(Context *ctx, bool print_fmax, bool print_path)
             auto net = port.net;
             unsigned i = 0;
             for (auto &usr : net->users)
-                if (&usr == sink) break;
-                else ++i;
+                if (&usr == sink)
+                    break;
+                else
+                    ++i;
             auto &driver = net->driver;
             auto driver_cell = driver.cell;
             delay_t comb_delay;
diff --git a/common/timing.h b/common/timing.h
index de4f7bbe..d0159d5c 100644
--- a/common/timing.h
+++ b/common/timing.h
@@ -24,11 +24,8 @@
 
 NEXTPNR_NAMESPACE_BEGIN
 
-// Assign "budget" values for all user ports in the design
-void assign_budget(Context *ctx);
-
 // Evenly redistribute the total path slack amongst all sinks on each path
-void update_budget(Context *ctx);
+void assign_budget(Context *ctx, bool quiet = false);
 
 // Perform timing analysis and return the minimum path slack,
 //   optionally, print out the fmax and critical path
diff --git a/ice40/arch.cc b/ice40/arch.cc
index cfafa2d8..2ca8b665 100644
--- a/ice40/arch.cc
+++ b/ice40/arch.cc
@@ -585,7 +585,7 @@ delay_t Arch::estimateDelay(WireId src, WireId dst) const
     // }
 
     // Estimate for output mux
-    for (const auto& bp : getWireBelPins(src)) {
+    for (const auto &bp : getWireBelPins(src)) {
         if (bp.pin == PIN_O && getBelType(bp.bel) == TYPE_ICESTORM_LC) {
             offset += 330;
             break;
@@ -593,8 +593,9 @@ delay_t Arch::estimateDelay(WireId src, WireId dst) const
     }
 
     // Estimate for input mux
-    for (const auto& bp : getWireBelPins(dst)) {
-        if ((bp.pin == PIN_I0 || bp.pin == PIN_I1 || bp.pin == PIN_I2 || bp.pin == PIN_I3) && getBelType(bp.bel) == TYPE_ICESTORM_LC) {
+    for (const auto &bp : getWireBelPins(dst)) {
+        if ((bp.pin == PIN_I0 || bp.pin == PIN_I1 || bp.pin == PIN_I2 || bp.pin == PIN_I3) &&
+            getBelType(bp.bel) == TYPE_ICESTORM_LC) {
             offset += 260;
             break;
         }
@@ -605,9 +606,9 @@ delay_t Arch::estimateDelay(WireId src, WireId dst) const
 
 delay_t Arch::getBudgetOverride(NetInfo *net_info, int user_idx, delay_t budget) const
 {
-    const auto& driver = net_info->driver;
+    const auto &driver = net_info->driver;
     if (driver.port == id_cout) {
-        const auto& sink = net_info->users[user_idx];
+        const auto &sink = net_info->users[user_idx];
         auto driver_loc = getBelLocation(driver.cell->bel);
         auto sink_loc = getBelLocation(sink.cell->bel);
         if (driver_loc.y == sink_loc.y)