Question

I have a function that, for argument sake, has two lines of code.

Line A
Line B

Both lines are calls to third party web service that does some work. It appears as though the service call on Line B is contingent on being called immediately (time-wise) after the call to Line A. This all works fine in a non-threaded environment but my application is threading lots (potentially 100) of these calls.

The problem with this threading, I believe, is that the context switching between the threads is causing enough time (a very small amount of time) to elapse between the call on Line A and the call on Line B that it’s causing the call on Line B to throw a custom soap exception.

My knowledge of threading doesn’t really extend to a situation like this. Is there anyway to make sure the call on Line B happens immediately after the call on Line A without thread context switching occurring in between?

Answer 1

If you need these lines to be called together then you can lock them, meaning that nothing else would enter this section until it is complete:

lock(lck)
{
    Line A
    Line B
}

However, this may cause you problems if this is all the 100 threads are doing – you lose your parallelism. In fact, whatever you do, if this is a general requirement, you will lose a degree of parallelism.