Pattern Design Concurrency Patterns 3

Question 1

The Pipeline concurrency pattern organizes computation as:

Accepted Answer

A series of processing stages where each stage transforms data and passes it downstream to the next stage

Answer

The Pipeline pattern decomposes a complex computation into sequential stages, each running in its own thread, so multiple items can be in-flight at different stages simultaneously.

Question 2

Which technique used in concurrent data structures divides the structure into independent segments, each guarded by its own lock, to reduce contention?

Accepted Answer

Lock Striping

Answer

Lock Striping partitions a data structure (e.g., a hash map) into stripes, each with its own lock, so threads operating on different stripes can proceed concurrently without blocking each other.

Question 3

The Compare-and-Swap (CAS) atomic operation is the fundamental building block for which class of concurrent algorithms?

Accepted Answer

Lock-free and wait-free algorithms that avoid traditional mutex locks

Answer

CAS atomically compares a memory location to an expected value and swaps it only if they match, enabling lock-free progress guarantees without blocking any thread.

Question 4

In the Proactor pattern, how are asynchronous operations handled?

Accepted Answer

The application initiates them and registers completion handlers that are invoked automatically when operations finish

Answer

Proactor lets the OS perform async I/O and then call application-supplied completion handlers, so the application thread is never blocked waiting for I/O to finish.

Question 5

Which concurrency pattern allows a thread to safely read data that another thread might be modifying, by working on a private copy rather than the shared original?

Accepted Answer

Copy-on-Write

Answer

Copy-on-Write defers copying a shared object until a mutation is needed; readers see the original without synchronization, and writers get a private copy to modify safely.

Pattern Design Practice Test

Pattern Design Practice Test

Pattern Design Concurrency Patterns 3