Just from looking at the stack trace, does --no-turbo-load-elimination resolve the issue? If so, I wonder if the pass could just abandon it's efforts in the presence of a large number of elements. I don't suppose you've tried reducing your case until the performance is acceptable? This would help gauge where the quadratic behaviour becomes too much.
Thanks, Sam On Thursday, June 29, 2023 at 5:40:12 AM UTC+1 Ben Noordhuis wrote: > On Thu, Jun 29, 2023 at 2:02 AM Andrey Sidorov <andrey....@gmail.com> > wrote: > > > > Hi, > > > > Crossposting from node, issue > https://github.com/nodejs/node/issues/48581 > > > > We have a CPU spike in a node process while no JS is being executed. The > time is likely spent in an optimiser thread. > > > > Steps to reproduce: run first script in > https://gist.github.com/sidorares/128160e6b3dea1da3ad45cd672651d2d#file-repro1-js > > and watch CPU at 100% for quite some time until the process exits. > > > > Stacktrace: > > > > * thread #5 * frame #0: 0x0000000101625d24 > node`v8::internal::compiler::LoadElimination::AbstractField::Kill(v8::internal::compiler::LoadElimination::AliasStateInfo > > const&, v8::internal::MaybeHandle<v8::internal::Name>, v8::internal::Zone*) > const + 68 frame #1: 0x00000001016287cb > node`v8::internal::compiler::LoadElimination::AbstractState::KillFields(v8::internal::compiler::Node*, > > v8::internal::MaybeHandle<v8::internal::Name>, v8::internal::Zone*) const + > 107 frame #2: 0x0000000101623484 > node`v8::internal::compiler::LoadElimination::ReduceStoreField(v8::internal::compiler::Node*, > > v8::internal::compiler::FieldAccess const&) + 900 frame #3: > 0x000000010155578a > node`v8::internal::compiler::Reducer::Reduce(v8::internal::compiler::Node*, > v8::internal::compiler::ObserveNodeManager*) + 26 frame #4: > 0x00000001016931e9 node`v8::internal::compiler::(anonymous > namespace)::SourcePositionWrapper::Reduce(v8::internal::compiler::Node*) + > 57 frame #5: 0x00000001015565aa > node`v8::internal::compiler::GraphReducer::Reduce(v8::internal::compiler::Node*) > > + 154 frame #6: 0x00000001015560f5 > node`v8::internal::compiler::GraphReducer::ReduceTop() + 613 frame #7: > 0x0000000101555c38 > node`v8::internal::compiler::GraphReducer::ReduceNode(v8::internal::compiler::Node*) > > + 216 frame #8: 0x0000000101693dee > node`v8::internal::compiler::LoadEliminationPhase::Run(v8::internal::compiler::PipelineData*, > > v8::internal::Zone*) + 718 frame #9: 0x000000010168501b node`auto > v8::internal::compiler::PipelineImpl::Run<v8::internal::compiler::LoadEliminationPhase>() > > + 123 frame #10: 0x00000001016818f7 > node`v8::internal::compiler::PipelineImpl::OptimizeGraph(v8::internal::compiler::Linkage*) > > + 455 frame #11: 0x00000001016814fe > node`v8::internal::compiler::PipelineCompilationJob::ExecuteJobImpl(v8::internal::RuntimeCallStats*, > > v8::internal::LocalIsolate*) + 142 frame #12: 0x000000010034a01b > node`v8::internal::OptimizedCompilationJob::ExecuteJob(v8::internal::RuntimeCallStats*, > > v8::internal::LocalIsolate*) + 43 frame #13: 0x00000001003778e3 > node`v8::internal::OptimizingCompileDispatcher::CompileNext(v8::internal::TurbofanCompilationJob*, > > v8::internal::LocalIsolate*) + 35 frame #14: 0x0000000100378359 > node`v8::internal::OptimizingCompileDispatcher::CompileTask::RunInternal() > + 425 frame #15: 0x000000010015304a node`node::(anonymous > namespace)::PlatformWorkerThread(void*) + 362 > > > > Is this a known issue/bug? > > Any hints on 1) how to reduce repro example even more 2) what is causing > the issue 3) any flags in node to test with optimiser on/off? > > > > Thanks, > > Andrey > > I forgot to mention it in the issue but the delay goes away when I > disable Turbofan with --noopt or --max-opt=2. > > Tested V8 version is 11.3.244.8-node.9. > -- -- v8-dev mailing list v8-dev@googlegroups.com http://groups.google.com/group/v8-dev --- You received this message because you are subscribed to the Google Groups "v8-dev" group. To unsubscribe from this group and stop receiving emails from it, send an email to v8-dev+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/v8-dev/7dc6b882-1cb8-4921-ad01-418c38d20714n%40googlegroups.com.
