Performance issues with our internal memory allocator

Noel Grandin noelgrandin at gmail.com
Mon Sep 28 06:29:11 PDT 2015



On 2015-09-28 03:11 PM, Markus Mohrhard wrote:
>
>
> I'm not sure if I understand your comment. Can you please clarify what you mean with that? Maybe my understanding of our
> memory allocators is bad but I see not how this comment applies to the discussion.
>

I'm saying that in general I regard changing allocators as doing optimisation in the wrong place - if your allocator is 
a real bottle-neck, you would probably be better off looking at optimising the code that __calls__ the allocator, rather 
than messing with the allocator itself.

For example, if you had code that did:
    vector<int> buffer;
    for (int i=0; i<1000000000; i++)
         buffer.push_back(i);
you'd be better off inserting a
    buffer.reserve(1000000000)
just before the loop, to avoid the std::vector's resize-and-copy operation.

But that's just my opinion, feel free to experiment away if allocators are your thing :-)



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