Subject: Re: [boost] [pool2] Requests for comment
From: Ion Gaztañaga (igaztanaga_at_[hidden])
Date: 2012-10-16 16:02:28
El 16/10/2012 15:06, Klaim - Joël Lamotte escribió:
> Stable vector don't guarantee contiguity but it apparently does keep bloc
> of objects contiguous as much as it can.
> If you reserve your optionals at first, then a lot of contiguous memory is
> allocated for your future objects, which is basically a pool.
> I'd say the main difference with boost::pool for example is that you can't
> have any input on the memory blocks boost::stable_vector will allocate.
stable_vector allocs nodes even when just reserving (and of course when
resizing). It keeps then in an internal pool as it offers better
exception guarantees than vector: it does not throw a memory error
exception (as memory was already reserved) and of course, it does not
have potentially throwing move operations when inserting in the middle.
> I might be wrong on the boost::stable_vector behaviour but my current tests
> shows that it's a win win scenario in my case.
If you reserve, then stable vector will call the allocator several times
to reserve memory and fill the internal pool. That memory is probably
contiguous (it depends on the allocator).
In the near future I hope to improve the performance of stable_vector
and other node containers adding "burst-allocation" extensions to a
general purpose heap allocator, an improved version of:
http://www.drivehq.com/web/igaztanaga/allocplus/#Chapter2
Current experiments are very encouraging.
Ion