[ https://issues.apache.org/jira/browse/KUDU-2727?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17142355#comment-17142355 ]
ASF subversion and git services commented on KUDU-2727: ------------------------------------------------------- Commit da1c66b61c4924a4726aaeb171e79cc0b03ca65c in kudu's branch refs/heads/master from Alexey Serbin [ https://gitbox.apache.org/repos/asf?p=kudu.git;h=da1c66b ] [consensus] KUDU-2727 lock-free CheckLeadershipAndBindTerm() This addresses the following lock contention issue outlined in KUDU-2727: tids=[93293,93284,93285,93286,93287,93288,93289,93290,93291,93292,93304,93294,93295,93296,93297,93298,93299,93300,93301,93302,93303,93313,93322,93321,93320,93319,93318,93317,93316,93315,93314,93283,93312,93311,93310,93309,93308,93307,93306,93305] 0x7f61b79fc5e0 <unknown> 0x1ec35f4 base::internal::SpinLockDelay() 0x1ec347c base::SpinLock::SlowLock() 0xb7deb8 kudu::consensus::RaftConsensus::CheckLeadershipAndBindTerm() 0xaab010 kudu::tablet::TransactionDriver::ExecuteAsync() 0xaa344c kudu::tablet::TabletReplica::SubmitWrite() 0x928fb0 kudu::tserver::TabletServiceImpl::Write() 0x1d2e8d9 kudu::rpc::GeneratedServiceIf::Handle() 0x1d2efd9 kudu::rpc::ServicePool::RunThread() 0x1ea4a84 kudu::Thread::SuperviseThread() 0x7f61b79f4e25 start_thread 0x7f61b5cd234d __clone tids=[93383] 0x7f61b79fc5e0 <unknown> 0x7f61b79f8cf2 __pthread_cond_timedwait 0x1dfcfa9 kudu::ConditionVariable::WaitUntil() 0xb73bc7 kudu::consensus::RaftConsensus::UpdateReplica() 0xb75128 kudu::consensus::RaftConsensus::Update() 0x92c5d1 kudu::tserver::ConsensusServiceImpl::UpdateConsensus() 0x1d2e8d9 kudu::rpc::GeneratedServiceIf::Handle() 0x1d2efd9 kudu::rpc::ServicePool::RunThread() 0x1ea4a84 kudu::Thread::SuperviseThread() 0x7f61b79f4e25 start_thread 0x7f61b5cd234d __clone In addition, with this patch RaftConsensus::DumpStatusHtml() no longer blocks Raft consensus activity and isn't blocked by it either. The inspiration for this update came from Yugabyte-DB: https://github.com/yugabyte/yugabyte-db/commit/7b3271e4a0f34ff3c3f6e8961288db9cee335461 Change-Id: I934ae3035d893fd850afe27d96f8dd6612c9ffbd Reviewed-on: http://gerrit.cloudera.org:8080/16034 Tested-by: Alexey Serbin <aser...@cloudera.com> Reviewed-by: Andrew Wong <aw...@cloudera.com> > Contention on the Raft consensus lock can cause tablet service queue overflows > ------------------------------------------------------------------------------ > > Key: KUDU-2727 > URL: https://issues.apache.org/jira/browse/KUDU-2727 > Project: Kudu > Issue Type: Improvement > Components: consensus, tserver > Reporter: William Berkeley > Assignee: Alexey Serbin > Priority: Major > Labels: performance, scalability > > Here's stacks illustrating the phenomenon: > {noformat} > tids=[2201] > 0x379ba0f710 <unknown> > 0x1fb951a base::internal::SpinLockDelay() > 0x1fb93b7 base::SpinLock::SlowLock() > 0xb4e68e kudu::consensus::Peer::SignalRequest() > 0xb9c0df kudu::consensus::PeerManager::SignalRequest() > 0xb8c178 kudu::consensus::RaftConsensus::Replicate() > 0xaab816 kudu::tablet::TransactionDriver::Prepare() > 0xaac0ed kudu::tablet::TransactionDriver::PrepareTask() > 0x1fa37ed kudu::ThreadPool::DispatchThread() > 0x1f9c2a1 kudu::Thread::SuperviseThread() > 0x379ba079d1 start_thread > 0x379b6e88fd clone > tids=[4515] > 0x379ba0f710 <unknown> > 0x1fb951a base::internal::SpinLockDelay() > 0x1fb93b7 base::SpinLock::SlowLock() > 0xb74c60 kudu::consensus::RaftConsensus::NotifyCommitIndex() > 0xb59307 kudu::consensus::PeerMessageQueue::NotifyObserversTask() > 0xb54058 > _ZN4kudu8internal7InvokerILi2ENS0_9BindStateINS0_15RunnableAdapterIMNS_9consensus16PeerMessageQueueEFvRKSt8functionIFvPNS4_24PeerMessageQueueObserverEEEEEEFvPS5_SC_EFvNS0_17UnretainedWrapperIS5_EEZNS5_34NotifyObserversOfCommitIndexChangeElEUlS8_E_EEESH_E3RunEPNS0_13BindStateBaseE > 0x1fa37ed kudu::ThreadPool::DispatchThread() > 0x1f9c2a1 kudu::Thread::SuperviseThread() > 0x379ba079d1 start_thread > 0x379b6e88fd clone > tids=[22185,22194,22193,22188,22187,22186] > 0x379ba0f710 <unknown> > 0x1fb951a base::internal::SpinLockDelay() > 0x1fb93b7 base::SpinLock::SlowLock() > 0xb8bff8 > kudu::consensus::RaftConsensus::CheckLeadershipAndBindTerm() > 0xaaaef9 kudu::tablet::TransactionDriver::ExecuteAsync() > 0xaa3742 kudu::tablet::TabletReplica::SubmitWrite() > 0x92812d kudu::tserver::TabletServiceImpl::Write() > 0x1e28f3c kudu::rpc::GeneratedServiceIf::Handle() > 0x1e2986a kudu::rpc::ServicePool::RunThread() > 0x1f9c2a1 kudu::Thread::SuperviseThread() > 0x379ba079d1 start_thread > 0x379b6e88fd clone > tids=[22192,22191] > 0x379ba0f710 <unknown> > 0x1fb951a base::internal::SpinLockDelay() > 0x1fb93b7 base::SpinLock::SlowLock() > 0x1e13dec kudu::rpc::ResultTracker::TrackRpc() > 0x1e28ef5 kudu::rpc::GeneratedServiceIf::Handle() > 0x1e2986a kudu::rpc::ServicePool::RunThread() > 0x1f9c2a1 kudu::Thread::SuperviseThread() > 0x379ba079d1 start_thread > 0x379b6e88fd clone > tids=[4426] > 0x379ba0f710 <unknown> > 0x206d3d0 <unknown> > 0x212fd25 google::protobuf::Message::SpaceUsedLong() > 0x211dee4 > google::protobuf::internal::GeneratedMessageReflection::SpaceUsedLong() > 0xb6658e kudu::consensus::LogCache::AppendOperations() > 0xb5c539 kudu::consensus::PeerMessageQueue::AppendOperations() > 0xb5c7c7 kudu::consensus::PeerMessageQueue::AppendOperation() > 0xb7c675 > kudu::consensus::RaftConsensus::AppendNewRoundToQueueUnlocked() > 0xb8c147 kudu::consensus::RaftConsensus::Replicate() > 0xaab816 kudu::tablet::TransactionDriver::Prepare() > 0xaac0ed kudu::tablet::TransactionDriver::PrepareTask() > 0x1fa37ed kudu::ThreadPool::DispatchThread() > 0x1f9c2a1 kudu::Thread::SuperviseThread() > 0x379ba079d1 start_thread > 0x379b6e88fd clone > {noformat} > {{kudu::consensus::RaftConsensus::CheckLeadershipAndBindTerm()}} needs to > take the lock to check the term and the Raft role. When many RPCs come in for > the same tablet, the contention can hog service threads and cause queue > overflows on busy systems. > Yugabyte switched their equivalent lock to be an atomic that allows them to > read the term and role wait-free. -- This message was sent by Atlassian Jira (v8.3.4#803005)