Subj : Re: Best locking methods
To   : comp.programming.threads
From : Uenal Mutlu
Date : Thu Apr 07 2005 04:35 am

"Joe Seigh" wrote
> On Wed, 6 Apr 2005 18:29:17 +0200, Uenal Mutlu wrote:
>
> > What is the best (fastest) method to synchronize access
> > to a memory block which is shared by say 5 reader threads
> > and 5 writer threads? The memblock can be realloced by
> > the writers and hence the pointer can change.
> > Platform is x86 Linux and Windows.
> >
> If contention is fairly low, then a simple pthread mutex or
> windows critical section will do.
>
> For high contention, a reader writer solution, lock-free
> COW (Copy On Write), is better.  You can use RCU, SMR,
> or atomic_ptr.  Don't bother with rwlocks which don't perform
> any better than mutexes.

IMHO COW and RCU would be slow with this data structure
since they seem to use a temporary copy, and I think the overhead
would be too costly.
Mutex is too slow; would need something faster than Critical Section.
I've yet to study how SMR and atomic_ptr do work.

.