Re: [boost] [lockfree] review

Subject: Re: [boost] [lockfree] review
From: Gottlob Frege (gottlobfrege_at_[hidden])
Date: 2011-11-05 01:20:12

On Sun, Oct 2, 2011 at 2:09 PM, Hans Boehm <Hans.Boehm_at_[hidden]> wrote:

> I think I see what you're doing.  By embedding the state of the queue into the
> same atomic object as the lock set bit, you can rely on single-location cache
> coherence to get the right ordering.  That can be made to work for the low-
> level bit-twiddling implementation, but not for a more generic approach that
> keeps the queue and the lock-bit itself separate.  I would still much rather
> see a default that works for the full solution space.  I prefer to have people
> like us who are sometimes willing to go through subtle reasoning about memory
> ordering add the annotations, rather than insisting that the average
> programmer who has never heard of these issues add them to avoid subtle bugs.
>
> Hans
>

I think that is the essence of the discussion.  I would say that
Alexander is of the opinion that the new atomics should have been
written for lock-free expert, whereas you might want them approachable
by the average programmer.  I worry about given atomics to the average
programmer.  Maybe they should have been harder to type than
reinterpret_cast.  I fully expect most uses (outside a library) to be
incorrect.

Tony