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  1. IMPALA
  2. IMPALA-2567 KRPC milestone 1
  3. IMPALA-6359

Blocking in Service threads due to tcmalloc contention due to memory allocations for RowBatch::Deserialize

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    Details

    • Type: Sub-task
    • Status: Resolved
    • Priority: Critical
    • Resolution: Duplicate
    • Affects Version/s: None
    • Fix Version/s: Not Applicable
    • Component/s: Distributed Exec
    • Labels:
      None
    • Epic Color:
      ghx-label-6

      Description

      This is a regression compared to thrift with KRPC is enabled.
      Results are based on running 48 concurrent TPCDS queries on a 40 node cluster, regression is in the order of 2-4x (Will update the JIRA with a more accurate number soon).

      Service threads stall on memory allocation in the stack below, looking at the Service threads memory allocation/deallocation I believe they won't benefit much from the per thread cache as there is more allocations than deallocations on this threads as a result they go to the CentralFreeList for most allocations.

      #0  0x00000000020931e7 in base::internal::SpinLockDelay(int volatile*, int, int) ()
      #1  0x00000000020dde29 in SpinLock::SlowLock() ()
      #2  0x0000000002121668 in tcmalloc::CentralFreeList::Populate() ()
      #3  0x0000000002121768 in tcmalloc::CentralFreeList::FetchFromOneSpansSafe(int, void**, void**) ()
      #4  0x00000000021217f4 in tcmalloc::CentralFreeList::RemoveRange(void**, void**, int) ()
      #5  0x000000000212ef53 in tcmalloc::ThreadCache::FetchFromCentralCache(unsigned long, unsigned long) ()
      #6  0x00000000021d37fb in tc_malloc ()
      #7  0x0000000000b27c3a in impala::MemPool::FindChunk(long, bool) ()
      #8  0x0000000000b354e6 in impala::MemPool::Allocate(long) ()
      #9  0x0000000000b34409 in impala::RowBatch::Deserialize(kudu::Slice const&, kudu::Slice const&, long, bool) ()
      #10 0x0000000000b347fb in impala::RowBatch::RowBatch(impala::RowDescriptor const*, impala::RowBatchHeaderPB const&, kudu::Slice const&, kudu::Slice const&, impala::MemTracker*) ()
      #11 0x0000000000b15d68 in impala::KrpcDataStreamRecvr::SenderQueue::AddBatchWork(long, impala::RowBatchHeaderPB const&, kudu::Slice const&, kudu::Slice const&, boost::unique_lock<impala::SpinLock>*) ()
      #12 0x0000000000b18715 in impala::KrpcDataStreamRecvr::SenderQueue::AddBatch(impala::TransmitDataRequestPB const*, kudu::rpc::RpcContext*) ()
      #13 0x0000000000b0e750 in impala::KrpcDataStreamMgr::AddData(impala::TransmitDataRequestPB const*, kudu::rpc::RpcContext*) ()
      #14 0x0000000001183305 in kudu::rpc::GeneratedServiceIf::Handle(kudu::rpc::InboundCall*) ()
      #15 0x00000000011bad7d in impala::ImpalaServicePool::RunThread() ()
      #16 0x0000000000d18a73 in impala::Thread::SuperviseThread(std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, boost::function<void ()()>, impala::Promise<long>*) ()
      

      I added logging to track allocations that take a long time and found that in the extreme case some allocations take up to 10 seconds when allocating 16KB of memory.

       MonotonicStopWatch timer;
          timer.Start();
          SCOPED_TIMER(recvr_->deserialize_row_batch_timer_);
          // At this point, the row batch will be inserted into batch_queue_. Close() will
          // handle deleting any unconsumed batches from batch_queue_. Close() cannot proceed
          // until there are no pending insertion to batch_queue_.
          batch.reset(new RowBatch(recvr_->row_desc(), header, tuple_offsets, tuple_data,
              recvr_->mem_tracker()));
          timer.Stop();
          if (timer.ElapsedTime() > 1000000) {
            LOG(INFO) << "TTT RowBatch allocation size:" << header.uncompressed_size() << " allocation time " << timer.ElapsedTime();
          }
      

      Call stacks from other threads that release RowBatch memory which also are affected by the tcmalloc contention

      #0  0x000000000212c1f4 in tcmalloc::PageHeap::MayMergeSpans(tcmalloc::Span*, tcmalloc::Span*) ()
      #1  0x000000000212c54d in tcmalloc::PageHeap::MergeIntoFreeList(tcmalloc::Span*) ()
      #2  0x000000000212c874 in tcmalloc::PageHeap::Delete(tcmalloc::Span*) ()
      #3  0x0000000002121090 in tcmalloc::CentralFreeList::ReleaseToSpans(void*) ()
      #4  0x000000000212111b in tcmalloc::CentralFreeList::ReleaseListToSpans(void*) ()
      #5  0x000000000212138c in tcmalloc::CentralFreeList::InsertRange(void*, void*, int) ()
      #6  0x000000000212f0f4 in tcmalloc::ThreadCache::ReleaseToCentralCache(tcmalloc::ThreadCache::FreeList*, unsigned long, int) ()
      #7  0x000000000212f1bc in tcmalloc::ThreadCache::ListTooLong(tcmalloc::ThreadCache::FreeList*, unsigned long) ()
      #8  0x00000000021d3d10 in tc_free ()
      #9  0x0000000000b26af8 in impala::MemPool::FreeAll() ()
      #10 0x0000000000b339b1 in impala::RowBatch::Reset() ()
      #11 0x0000000000fea7b1 in impala::PartitionedAggregationNode::Open(impala::RuntimeState*) ()
      #12 0x0000000000b77dfd in impala::FragmentInstanceState::Open() ()
      #13 0x0000000000b7943b in impala::FragmentInstanceState::Exec() ()
      #14 0x0000000000b68a0a in impala::QueryState::ExecFInstance(impala::FragmentInstanceState*) ()
      
      Thread 682 (Thread 0x7f61ebec4700 (LWP 28762)):
      #0  0x00000000020931e7 in base::internal::SpinLockDelay(int volatile*, int, int) ()
      #1  0x00000000020dde29 in SpinLock::SlowLock() ()
      #2  0x000000000212140f in tcmalloc::CentralFreeList::InsertRange(void*, void*, int) ()
      #3  0x000000000212f0f4 in tcmalloc::ThreadCache::ReleaseToCentralCache(tcmalloc::ThreadCache::FreeList*, unsigned long, int) ()
      #4  0x000000000212f1bc in tcmalloc::ThreadCache::ListTooLong(tcmalloc::ThreadCache::FreeList*, unsigned long) ()
      #5  0x00000000021d3d10 in tc_free ()
      #6  0x0000000000b338b1 in impala::RowBatch::~RowBatch() ()
      #7  0x0000000000d8d1e3 in impala::HdfsScanNode::GetNextInternal(impala::RuntimeState*, impala::RowBatch*, bool*) ()
      #8  0x0000000000d8ebf2 in impala::HdfsScanNode::GetNext(impala::RuntimeState*, impala::RowBatch*, bool*) ()
      #9  0x0000000000fee76e in impala::PartitionedHashJoinNode::NextProbeRowBatch(impala::RuntimeState*, impala::RowBatch*) ()
      #10 0x0000000000ff43b1 in impala::PartitionedHashJoinNode::GetNext(impala::RuntimeState*, impala::RowBatch*, bool*) ()
      #11 0x0000000000fee76e in impala::PartitionedHashJoinNode::NextProbeRowBatch(impala::RuntimeState*, impala::RowBatch*) ()
      #12 0x0000000000ff43b1 in impala::PartitionedHashJoinNode::GetNext(impala::RuntimeState*, impala::RowBatch*, bool*) ()
      #13 0x0000000000fee76e in impala::PartitionedHashJoinNode::NextProbeRowBatch(impala::RuntimeState*, impala::RowBatch*) ()
      #14 0x0000000000ff43b1 in impala::PartitionedHashJoinNode::GetNext(impala::RuntimeState*, impala::RowBatch*, bool*) ()
      #15 0x0000000000fea54d in impala::PartitionedAggregationNode::Open(impala::RuntimeState*) ()
      #16 0x0000000000b77dfd in impala::FragmentInstanceState::Open() ()
      #17 0x0000000000b7943b in impala::FragmentInstanceState::Exec() ()
      #18 0x0000000000b68a0a in impala::QueryState::ExecFInstance(impala::FragmentInstanceState*) ()
      #19 0x0000000000d18a73 in impala::Thread::SuperviseThread(std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, boost::function<void ()()>, impala::Promise<long>*) ()
      #20 0x0000000000d19204 in boost::detail::thread_data<boost::_bi::bind_t<void, void (*)(std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, boost::function<void ()()>, impala::Promise<long>*), boost::_bi::list4<boost::_bi::value<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, boost::_bi::value<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, boost::_bi::value<boost::function<void ()()> >, boost::_bi::value<impala::Promise<long>*> > > >::run() ()
      #21 0x000000000129bf5a in thread_proxy ()
      #22 0x000000326c607aa1 in start_thread () from /lib64/libpthread.so.0
      #23 0x000000326c2e893d in clone () from /lib64/libc.so.6
      

      This regression was observed with the tcmalloc options below

      TCMALLOC_MAX_TOTAL_THREAD_CACHE_BYTES=2147483648
      TCMALLOC_TRANSFER_NUM_OBJ=40
      

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              • Assignee:
                kwho Michael Ho
                Reporter:
                mmokhtar Mostafa Mokhtar
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                • Created:
                  Updated:
                  Resolved: