Re: [boost] Proposal: Monotonic Containers

Subject: Re: [boost] Proposal: Monotonic Containers
From: David Bergman (David.Bergman_at_[hidden])
Date: 2009-06-09 22:22:15

On Jun 9, 2009, at 9:48 PM, Christian Schladetsch wrote:

> Hi Cory,
>
>
>> My largest complaint with C++ is that containers do not fit well with
>> high-perf low-overhead scenarios, so I'm very interested in seeing
>> something like this.
>>
>> I would want to see it taken a step further though.  Overhead can  
>> be a
>> big deal for large objects, so re-implementing string and vector
>> completely (so that you don't have the pointer/capacity specified
>> twice, in container & allocator) would be a welcome change.
>
>
> I don't think anyone doing high-performance code uses std::string.

I have; when there has been no need to add to it - obviously - or deal  
with Unicode.

> It is a
> nightmare, and similarly for std::vector, for the reasons you claim.

I have...

Why would it be a nightmare using std::vector? The allocation  
mechanism, for the implementations I know, is not that bad, and one  
can always handle it pre-emptively, just as one would with  
"my_cool_buffer_array_like_thingie," especially with the kind of PODs  
one often deals with in high-performance operations. I just wonder if  
the problem you see with the allocation scheme is an algorithmic one  
or something specific to a certain implementation.

Putting allocation strategies aside - as in a lot of high-performance  
cases one is well aware of the "max buffer size" - what factors do you  
see of std::vector that is intrinsically, or in current  
implementations, limiting performance?

/David