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Re: Add cygwin_internal CW_GET_MODULE_PATH_FOR_ADDR


On Oct 15 10:15, Charles Wilson wrote:
> On 10/15/2011 4:51 AM, Corinna Vinschen wrote:
> >On Oct 15 01:00, Charles Wilson wrote:
> >> [stuff]
> >Sorry, I meant localename.c.  Almost everything for Win32 is done
> >for Cygwin as well.  Plus ignoring C.UTF-8 explicitly just on Cygwin.
> >That's cruel.
> 
> My working patch #ifdefs-out removes almost all of the code in localename.c.

Sounds good :)

> >Actually, since we have two types of relocation anyway, cheap and
> >expensive, why isn't it enough to have an expensive relocation using the
> >maps file?
> 
> Well, at the time I was thinking that if "expensive" could be made
> cheap *enough*, we could remove the distinction again.  The issue I
> have with Bruno's solution is that we now have three states, in the
> relocation code -- but only for cygwin.  And the states are
> controlled by two different mechanisms:
>   --disable-relocation + -UENABLE_COSTLY_RELOCATABLE (default) [*]
>   --enable-relocation + -UENABLE_COSTLY_RELOCATABLE
>   --enable-relocation + -DENABLE_COSTLY_RELOCATABLE
> 
> [*] subverted in libintl's Makefile with its -DENABLE_RELOCATABLE
> 
> That's just ugly.

I agree.

> >Somehow I missed the numbers.  How slow is accessing the
> >maps file in comparison?
> 
> 10-20x slower than linux -- 3 5o 5 ms per call, vs. 0.3 ms for
> linux. (Those are Bruno's timing investigation numbers).

And how often is the relocate function called?  It's sure slower than
Linux, but neither Linux nor Cygwin systems should need this code
anyway.  So, why is the Cygwin performance of a piece of code which
shouldn't be used so important?

> >I don't think it makes sense to add a cygwin_internal call for this
> >functionality.
> 
> OK. We can take this back to the main cygwin list now, then.

Fine with me.


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Project Co-Leader          cygwin AT cygwin DOT com
Red Hat


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