Multithreading Programming in C++ Training Course

Concurrency challenges and problems

• Hardware platform limitations - hardware threads, streams, cache memory coherence
• Basic concepts related to multithreaded programming (correctness of multithreaded programs, liveness, starvation, deadlock, race conditions, atomicity, consistency models, Flynn's taxonomy)
• Mechanisms available in C++ for implementing multithreading and multiprogramming
• Standard library implementation - elements from C++14 to the present (C++2a)
• Boost implementation - differences compared to the standard library

Processes and threads

• Multiprocess vs. multithreaded applications
• Operating system and threads (brief review of available implementations)
• Synchronization mechanisms for processes and threads
• Structural implementation of synchronization
• Specifics of multithreading implementation in an object-oriented approach (the role of the RAII pattern)

C++ memory model

• Objects and memory locations
• Ordering operations and enforcing them
• Relations: synchronization, happening-before, ordering operations for atomic actions, release sequences
• Memory barriers
• Atomic operations

Thread management in C++14 standard and later

• std::thread class and thread startup
• Thread identification
• Thread joining and detaching
• Threads and standard containers
• Exception handling in C++14 threads

Mutual exclusion and critical sections

• Basic principles of mutual exclusion
• Concepts (types) of available locking objects
• Brief introduction to time handling in C++14 (chrono library)
• std::mutex, std::timed_mutex, std::shared_mutex classes and derivatives
• RAII pattern in lock handling (std::lock_guard, std::unique_lock)
• Dependent and deferred locks (std::lock)
• Ownership and co-ownership of locks and threads
• The reader-writer problem
• One-time initialization
• Thread-local (private) memory (std::thread_local)

Locks and thread synchronization

• Semaphore operations
• Recursive locks
• Locks with a defined locking level
• Decision variables and cooperation with locks
• Implementation of active and passive barriers (Idle Waits, Busy Waits)
• Resuming thread operation
• Inter-thread communication (Actor model and CSP)

Asynchronous tasks

• Asynchronous events and their handling
• Futures
• Promises
• Packaged tasks

Atomic types

• Standard atomic types
• Universal atomic flag (std::atomic_flag)
• std::atomic<T> class template and its specializations
• Utility (free) functions for std::atomic types

Specifics of multithreaded API design

• Designing structures using locks - coarse-grained and fine-grained locks
• Performance of concurrent code - estimation and measurement techniques
• Data partitioning
• Scalability of solutions
• Error handling and exception situations in application architecture

Testing and debugging multithreaded applications

• Code reviews for multithreaded operations
• Specifics of testing multithreaded applications
• Unit tests
• Increasing the probability of failure scenarios for testing
• Formal methods for testing multithreaded applications
• Architecture patterns for multithreaded applications vs. testing and debugging (review)

Advanced thread management

• Dependent threads (Saga pattern)
• Avoiding contention in data access
• Controlled stopping and interrupting threads
• Interrupting blocking calls
• Interrupt handling
• Work stealing
• Interruption of tasks during application shutdown

Design patterns for multithreading

• Types and purposes of multithreading patterns
• Scope of pattern application
• Thread Pool
• Active Object pattern
• Thread Safe Queue
• Producer Consumer pattern
• Monitor pattern
• Multithreading safety of GoF patterns