Subj : Re: Lock Free -- where to start
To   : comp.programming.threads
From : chris noonan
Date : Thu Oct 06 2005 12:17 pm


Oliver S. wrote:
> >> If you really need performance, use thread-local pooling for
> >> memory allocations (the local pool may swap memory-blocks with
> > a global pool)
>
> > Swapping memory blocks - is that some sort of moveable memory?
>
> No, it just makes sense to give back pooled memory when the
> thread-local pool's size becomes to large.
>
> >> and if you need even more performance, use thread-local pools
> >> for equally sized objects. That's a magnitude faster than lock-free
> >> allocations on a global heap.
>
> > Which measurements of which lock-free allocator with a
> > global heap are you referring to?
>
> I don't need any concrete implementation to claim, that thread-local
> pooling with equally sized-blocks ist much faster than any lock-free
> allocator.

"A magnitude faster"? I think you do.

In any case your thread-local pool method could form the basis of
a lock-free allocator, rather than be contrasted to one. But
you omit to say how a memory block in a thread-local pool could
be freed by a thread other than the one that allocated it. That
is possible to arrange (Pentium processor) without a lock or even
a bus-locking instruction, but the extra complexity involved will
negate to some extent the time saved.

Chris

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