DLSM

Introduction

This project contains scripts and snippets in C++.

Features

• Build in Docker containers(Fedora, Ubuntu) or in current environment
• Build by GCC and Clang C++ compilers
• Build 3rd-party libraries by Conan
• Build C++ code coverage HTML report by LCOV with lines/functions/branches metrics
• Build with Thread/Address/UndefinedBehavior Sanitizer
• Integration with clang-format and clang-tidy
• Integration with Doxygen

Disruptor

Yet another implementation of LMAX Disruptor in C++20.

Details

Other known implementations

• Original LMAX Disruptor in Java
• Abc-Arbitrage/Disruptor-cpp
• lewissbaker/disruptorplus
• Vallest/Disruptor-CPP
• jeremyko/disruptorCpp-IPC

Features of dlsm::Disruptor

• Template-based implementation with different components for customization:
  • Barriers::
    • PointerBarrier - minimal container for dependencies of a sequence
    • AtomicsBarrier - std::atomic pointers to dependencies
    • OffsetsBarrier - std::atomic offsets to dependencies for placing in shared memory
  • Waits::
    • SpinsStrategy - busy-wait based on exponential __x86_64__ _mm_pause() intrinsic
    • YieldStrategy - busy-wait based on std::this_thread::yield()
    • BlockStrategy - blocking strategy based on std::std::condition_variable_any
    • ShareStrategy - blocking strategy based on pthreads for placing in shared memory
  • Sequencers::
    • SPMC - Single Producer Multiple Consumers pattern
    • MPMC - Multiple Producers Multiple Consumers pattern
  • Ring - adapter for external random-access container(std::array/vector) for ring-access to Events
• External memory injection(optional) for sequencers, useful for placement in HugePages/SharedMemory
• Unit and Performance(latency&throughput) tests
• dlsm::Disruptor::Graph - high-level API

Known defects and limitations

• Implementation of lock-free operations in not portable to Weak Memory Model platforms(ARM, PowerPC)
• Claim-Timeout/Consume-Timeout operations are not implemented in Sequencers(Publishers and Consumers)
• SPSC - Single Producer Single Consumer pattern is not implemented
• dlsm::Disruptor::Graph has high overhead caused by indirections and virtual calls
• dlsm::Disruptor::Graph is incomplete and unstable

Latency & Throughput tests

Results of performance tests are in separate tests/perf/Disruptor.md.

Useful Scripts

./scripts/format.sh   # Apply .clang-format rules on hpp/cpp files
./scripts/build.sh    # Perform all types of builds in current environment
./scripts/conan/build.sh Debug g++ coverage    # Build Debug by g++ with code coverage
./scripts/conan/build.sh Release clang++ tsan  # Build Release by clang++ with ThreadSanitizer
./scripts/docker/run.sh Ubuntu                     # Start Ubuntu.Dockerfile container in interactive mode
./scripts/docker/run.sh Fedora ./scripts/build.sh  # Perform all types of builds in Docker container
./scripts/docker/run.sh Fedora cat /etc/os-release # Perform command in Fedora.Dockerfile container
./scripts/docker/run.sh Ubuntu ./scripts/conan/build.sh Release g++ tsan ./build-ubuntu-tsan
./scripts/docker/run.sh Ubuntu ./scripts/conan/build.sh RelWithDebInfo g++ common ./build

Links and References

• Measuring Latency in Linux
• Weak vs. Strong Memory Models
• Fast and/or Large Memory – Cache and Memory Hierarchy