[Patch] mt_allocator: spare mem & fix alignment problems

[Paolo Carlini]

B. Kosnik wrote:

>Thanks. All this looks great!
>  
>
Thank you :)

>>Overall, the performance seem slightly improved (see attachments), but
>>perhaps the heuristics in deallocate should be tweaked again.
>>    
>>
>After you check this in I'll take it for a spin as well.
>  
>
In a moment I will...

>>Tested x86/x86_64/ia64 linux: now same results on all three, with the
>>only unsolved problem (wrt new/pool-allocator) of pthread7-rope.
>>    
>>
>This is really great news!
>
>I'm not quite sure what is up with pthread7-rope. Do you know if this
>fails if std::string is used instead of rope? I'm just curious.
>  
>
I have /no idea/, will look into that later today. I want also the check 
the effect of raising
_M_max_bytes to 256 or even 512 on 64-bit machines (the same actually 
applies to
pool_allocator)

Paolo.