Re: [boost] [XInt] CoW/Move Timings

Subject: Re: [boost] [XInt] CoW/Move Timings
From: Mathias Gaunard (mathias.gaunard_at_[hidden])
Date: 2011-03-10 04:00:13

On 10/03/2011 02:23, Chad Nelson wrote:

> I will make the updated code available on request for anyone who wants
> to examine the changes.
>
> 512bit
> CoW, no Move:    0.48, 0.47, 0.47: 0.48
> No CoW, no Move: 0.61, 0.61, 0.62: 0.61 (worst)
> No CoW, Move:    0.57, 0.57, 0.55: 0.56
> CoW, Move:       0.44, 0.44, 0.44: 0.44 (best)
>
> Review code,
>    CoW, no Move:  0.50, 0.47, 0.47: 0.48
>
> 2Kbit
> CoW, no Move:    4.69, 4.79, 4.89: 4.79 (best)
> No CoW, no Move: 5.01, 5.19, 5.06: 5.09 (worst)
> No CoW, Move:    5.18, 5.00, 5.01: 5.06
> CoW, Move:       4.80, 4.79, 4.86: 4.82
>
> Review code,
>    CoW, no Move:  4.88, 4.85, 4.94: 4.89
>
> 8Kbit
> CoW, no Move:    68.0, 68.8, 68.9: 68.6
> No CoW, no Move: 70.4, 70.4, 70.2: 70.3 (worst)
> No CoW, Move:    70.9, 69.8, 69.6: 70.1
> CoW, Move:       68.4, 68.2, 67.8: 68.1 (best)
>
> Review code,
>    CoW, no Move:  68.8, 68.4, 68.8: 68.7

In the move case, make your objects non-copiable to ensure you're not 
comparing oranges and apples.

Clearly, you have copies going on somewhere. Size of the buffer should 
not affect *at all* the performance of move.
Likewise the performance of COW should barely be affected.