Re: [boost] shifted_ptr<> w/ lock mechanism

From: David Abrahams (dave_at_[hidden])
Date: 2003-01-29 15:21:53

"Philippe A. Bouchard" <philippeb_at_[hidden]> writes:

> Lock mechanism was added to shifted_ptr<>:
> http://groups.yahoo.com/group/boost/files/shifted_ptr.zip
>
> Benchmarks are also updated.  Still shifted_ptr<> is using less memory and
> twice faster for reconstruction time.

Almost.

> Notes:
> - The first memory map report is not precise (shifted_ptr<U>).
> - The reports were reordered (shifted_ptr<U>, shifted_ptr<T> &
> shared_ptr<T>).
>
> I believe there is not that much left to do besides optimizations.

Have you tried a comparison against a shared_ptr using an optimized
count allocator?  Nobody has invested as much effort in optimizing
shared_ptr as you are pouring into shifted_ptr, but an experiment I
did years ago made a huge difference in the efficiency of shared_ptr
just by implementing a crude allocator for count objects (took me
about 10 minutes to code up).  For me to find shifted_ptr convincing
I'd have to see a noticeable performance improvement over using an
optimized count allocator with shared_ptr.

-- 
                       David Abrahams
   dave_at_[hidden] * http://www.boost-consulting.com
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