Re: [boost] [Block Pointer] benchmark

Subject: Re: [boost] [Block Pointer] benchmark
From: Nevin Liber (nevin_at_[hidden])
Date: 2011-05-25 01:52:30

On 24 May 2011 18:52, Phil Bouchard <philippe_at_[hidden]> wrote:

> On 5/24/2011 4:07 PM, Nevin Liber wrote:
>
>>
>> Your claim is " It is a fast as the popular smart pointer *
>> boost::shared_ptr<T>*".  Yet, in single-threaded code and shared_ptr using
>> new instead of make_shared, block_ptr still takes 3.3x as long as
>> shared_ptr.
>>
>> That is *a lot* of overhead...
>>
>
> I just tested it using make_shared & make_block and I get:
> make:
> auto_ptr:                   11109841 ns
> shared_ptr:                 21215277 ns
> block_ptr:                 143637475 ns
>
> new:
> auto_ptr                     4583447 ns
> shared_ptr:                 10675000 ns
> block_ptr:                  67152785 ns
>
> FYI make_shared is slower than new because of the temporary it creates.  If
> people what speed they should stick to operator new in all cases.

Heck, even auto_ptr is significantly faster using new instead of make_shared
and make_block.  Simply amazing!  Wait, ... how exactly did you use
make_shared and make_block in the auto_ptr case?

And that isn't nearly as amazing as your assertion that an increment and
decrement of a reference count (which is all that a shared_ptr "temporary"
translates into) is not only slower, but *significantly* slower than a heap
allocation/deallocation in the standard heap.
-- 
 Nevin ":-)" Liber  <mailto:nevin_at_[hidden]>  [phone]