Parallel tree traversal in C#

Question

I need to traverse a tree quickly, and I would like to do it in parallel. I\'d rather use the parallel extensions than manually spin up a bunch of threads.

My current co

Answer 1

Assuming you have p processors maybe you do a Parallel.For over root.Children with p partitions. Each of these would do the traditional single-thread traverse over the subtrees, compare, and, rather than DoSomething, would enqueue a delegate to DoSomething to a concurrent queue. If the distribution is basically random and balanced and since traversal only does traversal/enqueue, that portion takes 1/p th the time. Also, traversal would likely exhaust itself before all the DoSomethings would execute, so you could have p consumers (executors of DoSomething) giving you maximum parallel execution, assuming all these operations are independent.

With this naive partitioning across the number of root children with randomly distributed subtrees, traversal itself will be speedy. With your consumers roughly allocated per processor, you also get max parallel DoSomething action.