*nix pthreads really only provides condition variables and mutexs as thread-level mechanisms for safeguarding concurrency. At the system level, *nix typically provides semaphores, which can be a kind of combination of these (ie counting semaphores can be used to mimick similar behavior to condition variables). Semaphores are also system wide, and can be used to sync access to things beyond process scope (shared-mem, files, etc) I think you are misinformed about the performance of mutexes and condition vars. Both are quite fast, and do not, by default, involve polling. Even semaphores have very limited performance implications. here is what I consider to be a good description on the use of condition variables, and why mutexes are also necessary.

I work on a tcp-proxy system where performance is at a premium (on Linux), and the mutex/cond-wait mechanism is never even a blip when when we profile it looking for bottlenecks.

fnord

In reply to Re: OT: Locking and syncing mechanisms available on *nix. by Illuminatus
in thread OT: Locking and syncing mechanisms available on *nix. by BrowserUk

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