caiyu/nextpnr
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

static: First pass at timing-driven placement

Browse Source 
Signed-off-by: gatecat <gatecat@ds0.me>
This commit is contained in:
gatecat 2024-02-09 07:57:53 +01:00 committed by myrtle
parent cc273c1257
commit 255633c9f3
2 changed files with 39 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

37
common/place/placer_static.cc
View File

@ -795,7 +795,19 @@ class StaticPlacer
wl_coeff.at(axis) * pd.max_exp.at(axis) * x_max_sum) /
(max_sum * max_sum);
}
gradient += (d_min - d_max);
float crit = 0.0;
if (cfg.timing_driven) {
if (port.second.type == PORT_IN) {
crit = tmg.get_criticality(CellPortKey(cell->name, port.first));
} else if (port.second.type == PORT_OUT) {
if (ni && ni->users.entries() < 5) {
for (auto usr : ni->users)
crit = std::max(crit, tmg.get_criticality(CellPortKey(usr)));
}
}
}
float weight = 1.0 + 5 * std::pow(crit, 2);
gradient += weight * (d_min - d_max);
}
return gradient;
@ -975,6 +987,7 @@ class StaticPlacer
initial_steplength *= 10;
}
}
update_timing();
}
RealPair clamp_loc(RealPair loc)
@ -1034,6 +1047,26 @@ class StaticPlacer
update_gradients(true);
log_info(" system potential: %f hpwl: %f\n", system_potential(), system_hpwl());
compute_overlap();
if ((iter % 5) == 0)
update_timing();
}
void update_timing()
{
if (!cfg.timing_driven)
return;
for (auto &net : nets) {
NetInfo *ni = net.ni;
if (ni->driver.cell == nullptr)
continue;
RealPair drv_loc = cell_loc(ni->driver.cell, false);
for (auto usr : ni->users.enumerate()) {
RealPair usr_loc = cell_loc(usr.value.cell, false);
delay_t est_delay = cfg.timing_c + cfg.timing_mx * std::abs(drv_loc.x - usr_loc.x) + cfg.timing_my * std::abs(drv_loc.y - usr_loc.y);
tmg.set_route_delay(CellPortKey(usr.value), DelayPair(est_delay));
}
}
tmg.run(false);
}
void legalise_step(bool dsp_bram)
@ -1342,6 +1375,8 @@ class StaticPlacer
: ctx(ctx), cfg(cfg), fast_bels(ctx, true, 8), tmg(ctx), pool(ctx->setting<int>("threads", 8))
{
groups.resize(cfg.cell_groups.size());
tmg.setup_only = true;
tmg.setup();
};
void place()
{

3
ecp5/arch.cc
View File

@ -627,6 +627,9 @@ void configure_static(Arch *arch, PlacerStaticCfg &cfg)
comb.bel_area[id_MULT18X18D] = StaticRect(2.0f, 1.0f);
comb.spacer_rect = StaticRect(2.0f, 1.0f);
}
cfg.timing_c = (120 - 22 * arch->args.speed) * 6;
cfg.timing_mx = (120 - 22 * arch->args.speed);
cfg.timing_my = (120 - 22 * arch->args.speed);
}
} // namespace