Subj : Re: recursive mutexes
To   : comp.programming.threads
From : Uenal Mutlu
Date : Sun May 15 2005 05:59 pm

"Peter Dimov" wrote
> Uenal Mutlu wrote:
> > "David Schwartz" wrote
> >>     Yes, it can and must know that it already has the lock. A
> >> function that operates on X should be defined as being called with X
> >> locked, or with X unlocked. It could even take a boolean that
> >> indicates whether the caller has locked the object or not, though
> >> this is rarely the right thing to do.
> >
> > You are unnecessarily complicating things and make the program
> > slower by doing these testings.
>
> No, he's in fact making the program faster.

Are you sure? Let's see:

void X::f()
{
   Lock();
   for (int i = 0; i < 1000; i++)
     f();
   Unlock();
}

void X::g()
{
  if (!IsLocked())
    return;
  //...do..something...
}

Are you saying the above version of g() is faster than this one:  ?
void X::g()
{
  //...do..something...
}

.