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Merge pull request #1066 from arjenroodselaar/place_timeout

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Timeout when legal placement can't be found for cell
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myrtle 2022-12-21 07:10:09 +00:00 committed by GitHub
commit a80d63b268
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3 changed files with 26 additions and 6 deletions
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6
common/kernel/command.cc
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@ -189,6 +189,8 @@ po::options_description CommandHandler::getGeneralOptions()
general.add_options()("placer-heap-critexp", po::value<int>(),
"placer heap criticality exponent (int, default: 2)");
general.add_options()("placer-heap-timingweight", po::value<int>(), "placer heap timing weight (int, default: 10)");
general.add_options()("placer-heap-cell-placement-timeout", po::value<int>(),
"allow placer to attempt up to max(10000, total cells^2 / N) iterations to place a cell (int N, default: 8, 0 for no timeout)");
#if !defined(__wasm)
general.add_options()("parallel-refine", "use new experimental parallelised engine for placement refinement");
@ -328,6 +330,10 @@ void CommandHandler::setupContext(Context *ctx)
if (vm.count("placer-heap-timingweight"))
ctx->settings[ctx->id("placerHeap/timingWeight")] = std::to_string(vm["placer-heap-timingweight"].as<int>());
if (vm.count("placer-heap-cell-placement-timeout"))
ctx->settings[ctx->id("placerHeap/cellPlacementTimeout")] =
std::to_string(std::max(0, vm["placer-heap-cell-placement-timeout"].as<int>()));
if (vm.count("parallel-refine"))
ctx->settings[ctx->id("placerHeap/parallelRefine")] = true;

25
common/place/placer_heap.cc
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@ -218,7 +218,10 @@ class HeAPPlacer
heap_runs.push_back(all_buckets);
// The main HeAP placer loop
log_info("Running main analytical placer.\n");
if (cfg.cell_placement_timeout > 0)
log_info("Running main analytical placer, max placement attempts per cell = %d.\n", cfg.cell_placement_timeout);
else
log_info("Running main analytical placer.\n");
while (stalled < 5 && (solved_hpwl <= legal_hpwl * 0.8)) {
// Alternate between particular bel types and all bels
for (auto &run : heap_runs) {
@ -862,6 +865,7 @@ class HeAPPlacer
int radius = 0;
int iter = 0;
int iter_at_radius = 0;
int total_iters_for_cell = 0;
bool placed = false;
BelId bestBel;
int best_inp_len = std::numeric_limits<int>::max();
@ -878,11 +882,9 @@ class HeAPPlacer
}
while (!placed) {
// Set a conservative timeout
if (iter > std::max(10000, 3 * int(ctx->cells.size())))
log_error("Unable to find legal placement for cell '%s', check constraints and utilisation.\n",
ctx->nameOf(ci));
if (cfg.cell_placement_timeout > 0 && total_iters_for_cell > cfg.cell_placement_timeout)
log_error("Unable to find legal placement for cell '%s' after %d attempts, check constraints and utilisation. Use `--placer-heap-cell-placement-timeout` to change the number of attempts.\n",
ctx->nameOf(ci), total_iters_for_cell);
// Determine a search radius around the solver location (which increases over time) that is clamped to
// the region constraint for the cell (if applicable)
@ -1084,6 +1086,8 @@ class HeAPPlacer
break;
}
}
total_iters_for_cell++;
}
}
auto endt = std::chrono::high_resolution_clock::now();
@ -1814,6 +1818,15 @@ PlacerHeapCfg::PlacerHeapCfg(Context *ctx)
solverTolerance = 1e-5;
placeAllAtOnce = false;
int timeout_divisor = ctx->setting<int>("placerHeap/cellPlacementTimeout", 8);
if (timeout_divisor > 0) {
// Set a conservative default. This is a rather large number and could probably
// be shaved down, but for now it will keep the process from running indefinite.
cell_placement_timeout = std::max(10000, (int(ctx->cells.size()) * int(ctx->cells.size()) / timeout_divisor));
} else {
cell_placement_timeout = 0;
}
hpwl_scale_x = 1;
hpwl_scale_y = 1;
spread_scale_x = 1;

1
common/place/placer_heap.h
View File

@ -42,6 +42,7 @@ struct PlacerHeapCfg
float solverTolerance;
bool placeAllAtOnce;
bool parallelRefine;
int cell_placement_timeout;
int hpwl_scale_x, hpwl_scale_y;
int spread_scale_x, spread_scale_y;