# [INFO GPL-0075] Routability numCall: 1 inflationIterCnt: 1 bloatIterCnt: 0 Tool: Global Routing Subcategory: Stuck in routine ## Conversation ### oharboe So I thought my run was almost finished, it went fairly quickly for a while, but then it got stuck in "Routeability" below. 5 minutes until it got to the GPL-0075 progress message, then stuck there for at least 30 minutes. What does this mean and what can I do about it? The floorplan in my case looks quite reasonable and generous. https://github.com/The-OpenROAD-Project/OpenROAD/blob/580bd35a8b17f0ea7ff8afafb6cf6d23b757063e/src/gpl/src/routeBase.cpp#L557 ``` [NesterovSolve] Iter: 370 overflow: 0.254754 HPWL: 19171375971 [NesterovSolve] Iter: 380 overflow: 0.250836 HPWL: 18915207500 [NesterovSolve] Iter: 390 overflow: 0.225598 HPWL: 18784146027 [NesterovSolve] Iter: 400 overflow: 0.201047 HPWL: 18784861983 [INFO GPL-0075] Routability numCall: 1 inflationIterCnt: 1 bloatIterCnt: 0 ``` ### oharboe A little bit of suspend/resume profiling using latest OpenROAD and release build... Hmmm... curious. I don't think this is a performance problem, but there were a lot of exceptions thrown, so I had to turn off breakpoints on exceptions. ``` __cxa_throw (@__cxa_throw:3) sta::DmpAlg::findDriverParams(double) (.cold) (@sta::DmpAlg::findDriverParams(double) (.cold):14) sta::DmpPi::gateDelaySlew(double&, double&) (.cold) (@sta::DmpPi::gateDelaySlew(double&, double&) (.cold):50) sta::DmpCeffDelayCalc::gateDelay(sta::LibertyCell const*, sta::TimingArc const*, float const&, float, sta::Parasitic const*, float, sta::Pvt const*, sta::DcalcAnalysisPt const*, float&, float&) (@sta::DmpCeffDelayCalc::gateDelay(sta::LibertyCell const*, sta::TimingArc const*, float const&, float, sta::Parasitic const*, float, sta::Pvt const*, sta::DcalcAnalysisPt const*, float&, float&):88) sta::GraphDelayCalc1::findArcDelay(sta::LibertyCell*, sta::Pin const*, sta::Vertex*, sta::MultiDrvrNet*, sta::TimingArc*, sta::Parasitic*, float, sta::Vertex*, sta::Edge*, sta::Pvt const*, sta::DcalcAnalysisPt const*, sta::ArcDelayCalc*) (@sta::GraphDelayCalc1::findArcDelay(sta::LibertyCell*, sta::Pin const*, sta::Vertex*, sta::MultiDrvrNet*, sta::TimingArc*, sta::Parasitic*, float, sta::Vertex*, sta::Edge*, sta::Pvt const*, sta::DcalcAnalysisPt const*, sta::ArcDelayCalc*):112) sta::GraphDelayCalc1::findDriverEdgeDelays(sta::LibertyCell*, sta::Instance*, sta::Pin const*, sta::Vertex*, sta::MultiDrvrNet*, sta::Edge*, sta::ArcDelayCalc*) (@sta::GraphDelayCalc1::findDriverEdgeDelays(sta::LibertyCell*, sta::Instance*, sta::Pin const*, sta::Vertex*, sta::MultiDrvrNet*, sta::Edge*, sta::ArcDelayCalc*):105) sta::GraphDelayCalc1::findDriverDelays1(sta::Vertex*, bool, sta::MultiDrvrNet*, sta::ArcDelayCalc*) (@sta::GraphDelayCalc1::findDriverDelays1(sta::Vertex*, bool, sta::MultiDrvrNet*, sta::ArcDelayCalc*):108) sta::GraphDelayCalc1::findDriverDelays(sta::Vertex*, sta::ArcDelayCalc*) (@sta::GraphDelayCalc1::findDriverDelays(sta::Vertex*, sta::ArcDelayCalc*):63) sta::FindVertexDelays::visit(sta::Vertex*) (@sta::FindVertexDelays::visit(sta::Vertex*):74) sta::BfsIterator::visit(int, sta::VertexVisitor*) (@sta::BfsIterator::visit(int, sta::VertexVisitor*):71) sta::GraphDelayCalc1::findDelays(int) (@sta::GraphDelayCalc1::findDelays(int):47) sta::Sta::checkSlewLimitPreamble() (@sta::Sta::checkSlewLimitPreamble():82) rsz::RepairDesign::repairDesign(double, double, double, int&, int&, int&, int&, int&) (@rsz::RepairDesign::repairDesign(double, double, double, int&, int&, int&, int&, int&):65) rsz::Resizer::findResizeSlacks() (@rsz::Resizer::findResizeSlacks():24) gpl::TimingBase::updateGNetWeights(float) (@gpl::TimingBase::updateGNetWeights(float):18) gpl::NesterovPlace::doNesterovPlace(int) (@gpl::NesterovPlace::doNesterovPlace(int):1262) _wrap_replace_nesterov_place_cmd (@_wrap_replace_nesterov_place_cmd:20) TclNRRunCallbacks (@TclNRRunCallbacks:37) ___lldb_unnamed_symbol1504 (@___lldb_unnamed_symbol1504:315) Tcl_EvalEx (@Tcl_EvalEx:9) ``` Ooops.... from within the debugger(attaching) to the release build, I ran into an recursive loop below and a SEGFAULT. Curiously, this infinite stack recursion does not appear with the debug build, which makes for an interesting debug exercise... ``` rsz::RepairDesign::repairNetJunc(std::shared_ptr, int, int&, sta::Vector&) (@rsz::RepairDesign::repairNetJunc(std::shared_ptr, int, int&, sta::Vector&):16) rsz::RepairDesign::repairNet(std::shared_ptr, int, int&, sta::Vector&) (@rsz::RepairDesign::repairNet(std::shared_ptr, int, int&, sta::Vector&):82) [deleted 100s if not 1000s of these] (@rsz::RepairDesign::repairNet(std::shared_ptr, sta::Pin const*, float, int, sta::Corner const*):29) rsz::RepairDesign::repairNet(sta::Net*, sta::Pin const*, sta::Vertex*, bool, bool, bool, int, bool, int&, int&, int&, int&, int&) (@rsz::RepairDesign::repairNet(sta::Net*, sta::Pin const*, sta::Vertex*, bool, bool, bool, int, bool, int&, int&, int&, int&, int&):356) rsz::RepairDesign::repairDesign(double, double, double, int&, int&, int&, int&, int&) (@rsz::RepairDesign::repairDesign(double, double, double, int&, int&, int&, int&, int&):195) rsz::Resizer::findResizeSlacks() (@rsz::Resizer::findResizeSlacks():24) gpl::TimingBase::updateGNetWeights(float) (@gpl::TimingBase::updateGNetWeights(float):18) gpl::NesterovPlace::doNesterovPlace(int) (@gpl::NesterovPlace::doNesterovPlace(int):1262) _wrap_replace_nesterov_place_cmd (@_wrap_replace_nesterov_place_cmd:20) TclNRRunCallbacks (@TclNRRunCallbacks:37) ___lldb_unnamed_symbol1504 (@___lldb_unnamed_symbol1504:315) Tcl_EvalEx (@Tcl_EvalEx:9) Tcl_Eval (@Tcl_Eval:11) sta::sourceTclFile(char const*, bool, bool, Tcl_Interp*) (@sta::sourceTclFile(char const*, bool, bool, Tcl_Interp*):31) ord::tclAppInit(Tcl_Interp*) (@ord::tclAppInit(Tcl_Interp*):128) Tcl_MainEx (@Tcl_MainEx:111) main (@main:742) __libc_start_call_main (@__libc_start_call_main:29) __libc_start_main_impl (@__libc_start_main@@GLIBC_2.34:43) _start (@_start:15) ``` ### oharboe Letting it run for a while, debug is MUCH slower than release, I see when I suspend in the debugger. There are 200000 nets to process in gen_brk_RSMT(), coeffADJ() is going through double loops for a total of 10000000 iterations... ![image](https://user-images.githubusercontent.com/2798822/229814542-0e59488f-6f61-46ca-9219-fe4cea5fb085.png) ``` grt::FastRouteCore::getEdgeCapacity(grt::FrNet*, int, int, grt::EdgeDirection) (/home/oyvind/ascenium/OpenROAD-flow-scripts/tools/OpenROAD/src/grt/src/fastroute/src/FastRoute.cpp:592) grt::FastRouteCore::coeffADJ(int) (/home/oyvind/ascenium/OpenROAD-flow-scripts/tools/OpenROAD/src/grt/src/fastroute/src/RSMT.cpp:616) grt::FastRouteCore::gen_brk_RSMT(bool, bool, bool, bool, bool) (/home/oyvind/ascenium/OpenROAD-flow-scripts/tools/OpenROAD/src/grt/src/fastroute/src/RSMT.cpp:662) grt::FastRouteCore::run() (/home/oyvind/ascenium/OpenROAD-flow-scripts/tools/OpenROAD/src/grt/src/fastroute/src/FastRoute.cpp:766) grt::GlobalRouter::findRouting(std::vector>&, int, int) (/home/oyvind/ascenium/OpenROAD-flow-scripts/tools/OpenROAD/src/grt/src/GlobalRouter.cpp:397) grt::GlobalRouter::globalRoute(bool) (/home/oyvind/ascenium/OpenROAD-flow-scripts/tools/OpenROAD/src/grt/src/GlobalRouter.cpp:285) gpl::RouteBase::getGlobalRouterResult() (/home/oyvind/ascenium/OpenROAD-flow-scripts/tools/OpenROAD/src/gpl/src/routeBase.cpp:378) gpl::RouteBase::routability() (/home/oyvind/ascenium/OpenROAD-flow-scripts/tools/OpenROAD/src/gpl/src/routeBase.cpp:566) gpl::NesterovPlace::doNesterovPlace(int) (/home/oyvind/ascenium/OpenROAD-flow-scripts/tools/OpenROAD/src/gpl/src/nesterovPlace.cpp:699) gpl::Replace::doNesterovPlace(int) (/home/oyvind/ascenium/OpenROAD-flow-scripts/tools/OpenROAD/src/gpl/src/replace.cpp:343) replace_nesterov_place_cmd() (/home/oyvind/ascenium/OpenROAD-flow-scripts/tools/OpenROAD/build/src/gpl/CMakeFiles/gpl.dir/replaceTCL_wrap.cxx:1740) ::_wrap_replace_nesterov_place_cmd(ClientData, Tcl_Interp *, int, Tcl_Obj *const *) (/home/oyvind/ascenium/OpenROAD-flow-scripts/tools/OpenROAD/build/src/gpl/CMakeFiles/gpl.dir/replaceTCL_wrap.cxx:2190) TclNRRunCallbacks (@TclNRRunCallbacks:37) ___lldb_unnamed_symbol1504 (@___lldb_unnamed_symbol1504:315) Tcl_EvalEx (@Tcl_EvalEx:9) Tcl_Eval (@Tcl_Eval:11) sta::sourceTclFile(char const*, bool, bool, Tcl_Interp*) (/home/oyvind/ascenium/OpenROAD-flow-scripts/tools/OpenROAD/src/sta/app/StaMain.cc:95) ::tclAppInit(int &, char **, const char *, Tcl_Interp *) (/home/oyvind/ascenium/OpenROAD-flow-scripts/tools/OpenROAD/src/Main.cc:412) ord::tclAppInit(Tcl_Interp*) (/home/oyvind/ascenium/OpenROAD-flow-scripts/tools/OpenROAD/src/Main.cc:440) Tcl_MainEx (@Tcl_MainEx:111) ``` ![image](https://user-images.githubusercontent.com/2798822/229812113-27d8013b-9fbc-4727-93ee-18fed95d3702.png) ### maliberty You could try disabling each of these in turn to localize the cause ``` if {$::env(GPL_ROUTABILITY_DRIVEN)} { append global_placement_args " -routability_driven" } if {$::env(GPL_TIMING_DRIVEN)} { append global_placement_args " -timing_driven" } ``` The stacks in rsz/sta are related to timing_driven. If you see a stack in grt that is related to routability_driven.