Re: [Boost-users] [Pool] correct usage for optimal performance

Subject: Re: [Boost-users] [Pool] correct usage for optimal performance
From: mike marchywka (marchywka_at_[hidden])
Date: 2009-12-07 09:14:16

On 12/7/09, Igor R <boost.lists_at_[hidden]> wrote:
> Hello,
>
> In my application I use singleton pools for the 2 most common
> allocation scenarios:
>
> 1) Frequent allocation of small objects (one by one, tens to hundreds
> per second). Every object is disposed soon after its allocation, so
> that only few objects are alive simultaniously.
> Since the objects are accessed through shared_ptr, I allocate them as
> follows:
>
> allocate_shared<Obj>(boost::fast_pool_allocator<Obj>());
>
> Is this the appropriate use of Pool for this scenario? Should I use
> pool_allocator (i.e. ordered_malloc()) instead?
>
> 2) Frequent (same as in (1) frequency and lifetime) allocation of
> memory blocks that look like this: [10Kb, 1Kb, 1.1Kb, 0.9Kb,...
> 10.5Kb...] - i.e. 1 big block, then several small ones. Each block is
> stored in shared_array, and I allocate it this way:
>
> shared_array<char> data_;
> //...
> typedef boost::singleton_pool<my_alloc_tag, 1024> allocator;
> int chunks = blockSize / allocator::requested_size + 1; // rough
> aproximation
> data_.reset(static_cast<char *>(allocator::malloc(chunks)),
> bind(&allocator::free, _1, chunks));
>
> Again, should I use here ordered_xxx? Or probably it's worth using
> allocator::maloc for the case of chunks==1, and ordered_malloc for
> chunks > 1?
>

I guess I would ask you and boost people about memory hierarchy issues.
Is boost cache aware and how does the user tell boost about access patterns?
Often locality and the avoidance of cache thrashing can be a big
performance issue with complicated algorithms or large data sets.

> Thanks!
> _______________________________________________
> Boost-users mailing list
> Boost-users_at_[hidden]
> http://lists.boost.org/mailman/listinfo.cgi/boost-users
>

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