Re: [Boost-users] How to improve property_tree performance

Subject: Re: [Boost-users] How to improve property_tree performance
From: Sebastian Redl (sebastian.redl_at_[hidden])
Date: 2010-10-13 04:33:06

On 13.10.2010 10:15, Bo Jensen wrote:
>
> I tried that, it was only slightly faster. I also tried to do a bunch
> of independent trees and then merge them later, but still same speed.
> Is it correct, that you can not choose the underlying storage method
> or preallocate some space ? In my case I know exactly the sizes of
> each tree and number of items.
>    
No, because of the way PTree is structured at the high level (nesting 
trees where each branch can be treated as an independent tree), 
providing generic allocator support is impractical. Internally, a tree 
node consists of its local value and a node-based container of children, 
so preallocation through an interface would only be able to provide 
storage for that particular node, and would also require a special 
allocator.
However, if you want to try the performance effect of using a stateless 
Boost Pool allocator, I believe all you have to do is add it to the 
base_container typedef in 
boost/property_tree/detail/ptree_implementation.hpp, near the top. See 
that big multi_index_container? That's the storage for child nodes. If 
you give it an alternative (stateless!) allocator, it will be used.

Sebastian