Re: [boost] [circular buffer review]

From: Jan Gaspar (jano_gaspar_at_[hidden])
Date: 2004-03-13 10:23:56

Hi Thorsten!

--- Thorsten Ottosen <nesotto_at_[hidden]> wrote:

> I'm in doubt. The library has efficiency as its
> hallmark. The  rationale
> says that it
> gives efficient FIFO queue. So I tried to compare it
> with std::deque, and
> here is my results
> of an /O2 build with vc71:
> 
> $ ./cbuffer_vs_deque.exe
> 
>  circular_buffer<int>: 2.15 s
> 
> 
>  deque<int>: 2.84 s
> 
> 
>  circular_buffer<string>: 20.59 s
> 
> 
>  deque<string>: 18.64 s
> 
I compiled your test and made some experiments with
it. My results are:

circular_buffer<int>: 2.84 s
deque<int>: 3.84 s

circular_buffer<string>: 27.65 s
deque<string>: 25.65 s

struct test_struct {
        double d;
};

circular_buffer<test_struct>: 3.15 s
deque<test_struct>: 4.22 s

struct test_struct2 {
        double d1;
        double d2;
        double d3;
        double d4;
        double d5;
};

circular_buffer<test_struct2>: 7.67 s
deque<test_struct2>: 6.47 s

It seems to me that if you use circular_buffer for
storing "small" elements the circular_buffer is about
30% faster than deque. If you use larger elements the
deque is faster about 10%. (I did also experiments
with buffer size, but the results were about the
same.) I don't have an explanation for such behavour.
(Does anyone have?)

So, the result is: the circular_buffer is more
effective for storing primitive types.

Btw, at the early stages of library developmet I
implemented the circular_buffer as std::deque adaptor.
The problem was that there was no control over
iterator invalidation.

Best regards,

Jan

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