Intel Threading Building Blocks

Chapter 5. Containers

Intel Threading Building Blocks provides highly concurrent containers that permit multiple threads to invoke a method simultaneously on the same container. At this time, a concurrent queue, vector, and hash map are provided. All of these highly concurrent containers can be used with this library, OpenMP, or raw threads.

Highly concurrent containers are very important because Standard Template Library (STL) containers generally are not concurrency-friendly, and attempts to modify them concurrently can easily corrupt the containers. As a result, it is standard practice to wrap a lock (mutex) around STL containers to make them safe for concurrent access, by letting only one thread operate on the container at a time. But that approach eliminates concurrency, and thus is not conducive to multi-core parallelism.

As much as possible, the interfaces of the Threading Building Blocks containers are similar to STL, but they do not match completely because some STL interfaces are inherently not thread-safe. The Threading Building Blocks containers provide fine-grained locking or lock-free implementations, and sometimes both.

Fine-grained locking

Multiple threads operate on the container by locking only those portions they really need to lock. As long as different threads access different portions, they can proceed concurrently.

Lock-free algorithms

Different threads proceed straight through the operation without locks, accounting for and correcting the effects of other interfering ...