Re: [boost] Boost pool allocator slower than STL allocator

From: Robin (al_at_[hidden])
Date: 2007-12-30 22:08:11

> My understanding is that the pool allocator is made for repeated
> allocation and deallocation of same-sized blocks, in which case the
> result makes sense.  I think it's more intended for use with
> node-based containers such as list and map.

I tried with list, the std::allocator is still faster

typedef list <A, boost::pool_allocator <list <A>::value_type > > ListA;
ListA listA;

then 

listA.push_back (A ());
listA.pop_front ();

Or with boost::shared_ptr as I need to keep a polymorphic pointer.

typedef list < boost::shared_ptr <A>, boost::pool_allocator <A> > ListA;
ListA listA;

then

listA.push_back (boost::shared_ptr <A> (new A ()));
listA.pop_front ();

I can't get map to compile, 

typedef map <string, A, boost::pool_allocator <std::map <string,A>::value_type > 
> MapA;
MapA mapA;

mapA.insert (make_pair ("test",A ()));

VC8 balks at this line at the xutility comparision predicate header. It compiles 
fine with the std allocator.

Am I using pool incorrectly?

Robin

> On 30/12/2007, Robin <al_at_[hidden]> wrote:
>> I've been testing out boost pool allocator, and my results shows
>> it's slower
>> than the STL allocator. I'm using VSNet 2005 SP1. See test code
>> below.
>>
>
> My understanding is that the pool allocator is made for repeated
> allocation and deallocation of same-sized blocks, in which case the
> result makes sense.  I think it's more intended for use with
> node-based containers such as list and map.