Concurrency

• concurrency related code should be kept separate from other code.
• limit the scope of data as much as possible to avoid race conditions - e.g. only access shared data in one point of the code (no duplication!) so you can't accidentally forget to protect/lock the data elsewhere.
  • Change object design of shared data so that you don't force objects using the data to manage sharing as well
• Use copies instead of sharing when possible (e.g. local copy to a thread to be merged later in the main thread)
• threads should be as independent as possible - share as little with other threads as possible
• most concurrent problems are variations of the reader-writer, producer-consumer, and dining philosophers problems
• keep critical sections as small as possible