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Merge pull request #882 from YosysHQ/gatecat/router1-tmg-ripup

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router1: Experimental timing-driven ripup support
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gatecat 2021-12-18 21:49:48 +00:00 committed by GitHub
commit 56d5507333
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3 changed files with 103 additions and 6 deletions
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8
common/command.cc
View File

@ -176,7 +176,9 @@ po::options_description CommandHandler::getGeneralOptions()
general.add_options()("router2-heatmap", po::value<std::string>(),
"prefix for router2 resource congestion heatmaps");
general.add_options()("router2-tmg-ripup", "enable experimental timing-driven ripup in router2");
general.add_options()("tmg-ripup", "enable experimental timing-driven ripup in router");
general.add_options()("router2-tmg-ripup",
"enable experimental timing-driven ripup in router (deprecated; use --tmg-ripup instead)");
general.add_options()("report", po::value<std::string>(),
"write timing and utilization report in JSON format to file");
@ -298,8 +300,8 @@ void CommandHandler::setupContext(Context *ctx)
ctx->settings[ctx->id("placerHeap/timingWeight")] = std::to_string(vm["placer-heap-timingweight"].as<int>());
if (vm.count("router2-heatmap"))
ctx->settings[ctx->id("router2/heatmap")] = vm["router2-heatmap"].as<std::string>();
if (vm.count("router2-tmg-ripup"))
ctx->settings[ctx->id("router2/tmg_ripup")] = true;
if (vm.count("tmg-ripup") || vm.count("router2-tmg-ripup"))
ctx->settings[ctx->id("router/tmg_ripup")] = true;
// Setting default values
if (ctx->settings.find(ctx->id("target_freq")) == ctx->settings.end())

97
common/router1.cc
View File

@ -119,8 +119,11 @@ struct Router1
TimingAnalyser tmg;
bool timing_driven = true;
Router1(Context *ctx, const Router1Cfg &cfg) : ctx(ctx), cfg(cfg), tmg(ctx)
{
timing_driven = ctx->setting<bool>("timing_driven");
tmg.setup();
tmg.run();
}
@ -647,7 +650,7 @@ struct Router1
}
}
next_penalty += penalty_delta * std::max(0.05, (1.0 - crit));
next_penalty += penalty_delta * (timing_driven ? std::max(0.05, (1.0 - crit)) : 1);
delay_t next_score = next_delay + next_penalty;
NPNR_ASSERT(next_score >= 0);
@ -790,6 +793,53 @@ struct Router1
return true;
}
delay_t find_slack_thresh()
{
// If more than 5% of arcs have negative slack; use the 5% threshold as a ripup criteria
int arc_count = 0;
int failed_count = 0;
delay_t default_thresh = ctx->getDelayEpsilon();
for (auto &net : ctx->nets) {
NetInfo *ni = net.second.get();
if (skip_net(ni))
continue;
for (size_t i = 0; i < ni->users.size(); i++) {
auto &usr = ni->users.at(i);
++arc_count;
delay_t slack = tmg.get_setup_slack(CellPortKey(usr));
if (slack == std::numeric_limits<delay_t>::min())
continue;
if (slack < default_thresh)
++failed_count;
}
}
if (arc_count < 50 || (failed_count < (0.05 * arc_count))) {
return default_thresh;
}
std::vector<delay_t> slacks;
for (auto &net : ctx->nets) {
NetInfo *ni = net.second.get();
if (skip_net(ni))
continue;
for (size_t i = 0; i < ni->users.size(); i++) {
auto &usr = ni->users.at(i);
delay_t slack = tmg.get_setup_slack(CellPortKey(usr));
if (slack == std::numeric_limits<delay_t>::min())
continue;
slacks.push_back(slack);
}
}
std::sort(slacks.begin(), slacks.end());
delay_t thresh = slacks.at(int(slacks.size() * 0.05));
log_warning("%.f%% of arcs have failing slack; using %.2fns as ripup threshold. Consider a reduced Fmax "
"constraint.\n",
(100.0 * failed_count) / arc_count, ctx->getDelayNS(thresh));
return thresh;
}
};
} // namespace
@ -831,6 +881,9 @@ bool router1(Context *ctx, const Router1Cfg &cfg)
int iter_cnt = 0;
int last_arcs_with_ripup = 0;
int last_arcs_without_ripup = 0;
int timing_fail_count = 0;
bool timing_ripup = ctx->setting<bool>("router/tmg_ripup", false);
delay_t ripup_slack = 0;
log_info(" | (re-)routed arcs | delta | remaining| time spent |\n");
log_info(" IterCnt | w/ripup wo/ripup | w/r wo/r | arcs| batch(sec) total(sec)|\n");
@ -866,6 +919,48 @@ bool router1(Context *ctx, const Router1Cfg &cfg)
#endif
return false;
}
// Timing driven ripup
if (timing_ripup && router.arc_queue.empty() && timing_fail_count < 50) {
++timing_fail_count;
router.tmg.run();
delay_t wns = 0, tns = 0;
if (timing_fail_count == 1)
ripup_slack = router.find_slack_thresh();
for (auto &net : ctx->nets) {
NetInfo *ni = net.second.get();
if (router.skip_net(ni))
continue;
bool is_locked = false;
for (auto &wire : ni->wires) {
if (wire.second.strength > STRENGTH_STRONG)
is_locked = true;
}
if (is_locked)
continue;
for (size_t i = 0; i < ni->users.size(); i++) {
auto &usr = ni->users.at(i);
delay_t slack = router.tmg.get_setup_slack(CellPortKey(usr));
if (slack == std::numeric_limits<delay_t>::min())
continue;
if (slack < 0) {
wns = std::min(wns, slack);
tns += slack;
}
if (slack <= ripup_slack) {
for (WireId w : ctx->getNetinfoSinkWires(ni, usr)) {
if (ctx->checkWireAvail(w))
continue;
router.ripup_wire(w);
}
}
}
}
log_info(" %d arcs ripped up due to negative slack WNS=%.02fns TNS=%.02fns.\n",
int(router.arc_queue.size()), ctx->getDelayNS(wns), ctx->getDelayNS(tns));
iter_cnt = 0;
router.wireScores.clear();
router.netScores.clear();
}
}
auto rend = std::chrono::high_resolution_clock::now();
log_info("%10d | %8d %10d | %4d %5d | %9d| %10.02f %10.02f|\n", iter_cnt, router.arcs_with_ripup,

4
common/router2.cc
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@ -1373,8 +1373,8 @@ struct Router2
route_queue.push_back(i);
timing_driven = ctx->setting<bool>("timing_driven");
if (ctx->settings.count(ctx->id("router2/tmg_ripup")))
timing_driven_ripup = timing_driven && ctx->setting<bool>("router2/tmg_ripup");
if (ctx->settings.count(ctx->id("router/tmg_ripup")))
timing_driven_ripup = timing_driven && ctx->setting<bool>("router/tmg_ripup");
else
timing_driven_ripup = false;
log_info("Running main router loop...\n");