Can I force cache coherency on a multicore x86 CPU?

Question

The other week, I wrote a little thread class and a one-way message pipe to allow communication between threads (two pipes per thread, obviously, for bidirectional communica

Answer 1

You didn't specify which compiler you are using, but if you're on windows, take a look at this article here. Also take a look at the available synchronization functions here. You might want to note that in general volatile is not enough to do what you want it to do, but under VC 2005 and 2008, there are non-standard semantics added to it that add implied memory barriers around read and writes.

If you want things to be portable, you're going to have a much harder road ahead of you.

Answer 2

Herb Sutter seemed to simply suggest that any two variables should reside on separate cache lines. He does this in his concurrent queue with padding between his locks and node pointers.

Edit: If you're using the Intel compiler or GCC, you can use the atomic builtins, which seem to do their best to preempt the cache when possible.

Answer 3

The following is a good article in reference to using volatile w/ threaded programs.

Volatile Almost Useless for Multi-Threaded Programming.