Subj : speed-up critical regions
To   : comp.programming.threads
From : amorox
Date : Tue Jun 14 2005 05:13 pm

Hi everybody,

I'm trying to optimize the time needed to enter in a critical region
when it is consecutively executed in the same thread.
My idea was to use the RECURSIVE mutexes since the cost of a 'lock' on
an owned mutex is much less than on a non-owned mutex.

So, I tried something like this:

function init() {
   create RECURSIVE mutex;
   lock(mutex);
}

function critical_region() {
  if (trylock(mutex)) { // costs nothing if the mutex is owned by the
current thread
    unlock(mutex); // problem - I'm not the owner of the mutex
    lock(mutex);
    lock(mutex);
  }

  work();
  unlock(mutex);
}

function destroy() {
  unlock(mutex);
  destroy mutex;
}

As you can see the problem is in the 'unlock' operation I have to do
without being the mutex owner.
Is there any portable code for this?

Thankfully,
Ovidiu

.