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nexus: add option to modify the mult factor of the estimate delay

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Signed-off-by: Alessandro Comodi <acomodi@antmicro.com>
This commit is contained in:
Alessandro Comodi 2022-01-25 17:46:54 +01:00
parent e069b3bc6a
commit 676e56e5d4
3 changed files with 11 additions and 1 deletions
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7
nexus/arch.cc
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@ -601,7 +601,8 @@ delay_t Arch::estimateDelay(WireId src, WireId dst) const
int dst_x = dst.tile % chip_info->width, dst_y = dst.tile / chip_info->width;
int dist_x = std::abs(src_x - dst_x);
int dist_y = std::abs(src_y - dst_y);
return 75 * dist_x + 75 * dist_y + 250;
return estimate_delay_mult * (dist_x + dist_y) + 250;
}
delay_t Arch::predictDelay(BelId src_bel, IdString src_pin, BelId dst_bel, IdString dst_pin) const
{
@ -655,6 +656,10 @@ ArcBounds Arch::getRouteBoundingBox(WireId src, WireId dst) const
bool Arch::place()
{
estimate_delay_mult = 75;
if (getCtx()->settings.count(getCtx()->id("estimate-delay-mult")))
estimate_delay_mult = getCtx()->setting<int>("estimate-delay-mult");
std::string placer = str_or_default(settings, id("placer"), defaultPlacer);
if (placer == "heap") {

1
nexus/arch.h
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@ -1290,6 +1290,7 @@ struct Arch : BaseArch<ArchRanges>
// -------------------------------------------------
int32_t estimate_delay_mult;
delay_t estimateDelay(WireId src, WireId dst) const override;
delay_t predictDelay(BelId src_bel, IdString src_pin, BelId dst_bel, IdString dst_pin) const override;
delay_t getDelayEpsilon() const override { return 20; }

4
nexus/main.cc
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@ -54,6 +54,8 @@ po::options_description NexusCommandHandler::getArchOptions()
specific.add_options()("no-pack-lutff", "disable packing (clustering) LUTs and FFs together");
specific.add_options()("carry-lutff-ratio", po::value<float>(),
"ratio of FFs to be added to carry-chain LUT clusters");
specific.add_options()("estimate-delay-mult", po::value<int>(),
"multiplier for the estimate delay");
return specific;
}
@ -88,6 +90,8 @@ std::unique_ptr<Context> NexusCommandHandler::createContext(dict<std::string, Pr
}
ctx->settings[ctx->id("carry_lutff_ratio")] = ratio;
}
if (vm.count("estimate-delay-mult"))
ctx->settings[ctx->id("estimate-delay-mult")] = vm["estimate-delay-mult"].as<int>();
return ctx;
}