Minimize lock time

[Justin Spahr-Summers]

On Thu, 10 Jun 2010 12:42:09 +0200, Simen kjaeraas 
<simen.kjaras at gmail.com> wrote:
> 
> Kagamin <spam at here.lot> wrote:
> 
> > Let's consider the following code:
> >
> > synchronized(syncRoot)
> > {
> >   if(condition)opSuccess();
> >   else writeln(possibly,slow);
> > }
> >
> > Suppose the else close doesn't need to be executed in lock domain and  
> > can be slow. How to minimize lock time here?
> >
> > synchronized(syncRoot)
> > {
> >   if(condition)opSuccess();
> >   else goto Lwrite;
> > }
> > Lwrite: writeln(possibly,slow);
> >
> > We can do this... but...
> 
> A flag, as has been mentioned, would work.
> 
> Other solutions that might work:
> 
> ////////
> synchronized(syncRoot)
> {
>    if (condition)
>    {
>      opSuccess();
>      return;
>    }
> }
> writeln(possibly,slow);
> 
> ////////
> do
> {
>    synchronized(syncRoot)
>    {
>      if (condition)
>      {
>        opSuccess();
>        break;
>      }
>    }
>    writeln(possibly, slow);

All good suggestions. synchronized(), in general, just doesn't scale 
very well (though no fault of D's). If you're doing very complex things, 
you might have better luck with a semaphore of some kind. As always, 
though, avoiding the need for synchronization is best.