[v3] default linux allocator

[Mark Mitchell]

Benjamin Kosnik wrote:

>>If you think that all GNU/Linux users should have this new behavior, 
>>then it should be the default in the configury.  But, on the 3.4 branch, 
>>we should convince ourselves that (a) it's not an ABI change, and (b) 
>>it's a major win.
>>    
>>
>
>After reviewing performance testresults on x86, ppc, and x86_64, I think
>it is a major win.
>  
>
Can you say a bit more?  Technically, what does this change do and how 
does it improve performance?

>I don't see how this is an ABI change, linkage-wise: all the
>instantiations for char and wchar_t instantiations remain, for all the
>allocators. For other instantiations, there are no exports and thus
>local implicit copies of required symbols are assumed.
>  
>
What if you recompile half of the .o files in your program and not the 
other half?  Do you known have containers in one half using one 
allocator and containers in the other using the other half?  And if so, 
does that work?

Thanks,

-- 
Mark Mitchell
CodeSourcery, LLC
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mark@codesourcery.com