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From Jeff Trawick <traw...@attglobal.net>
Subject Re: apr_atomic stuff... desireable to return values from more functions
Date Thu, 04 Dec 2003 12:52:45 GMT
gregames@apache.org wrote:

> If apr_atomic_inc32 returns something, it would be much more useful to 
> have it return the old value of the variable.  That way you can 
> atomically allocate a slot in an array via:

you're the boss; fwliw, that sounds right to me

> IIRC the main objection to having this set of functions return something 
> was that we didn't have a fast implementation.  Now I've got a working 
> Intel version using the xadd instruction (which requires at least an 
> i486...is that a big deal?).

I don't think it is a big deal, but I'm curious about whether some folks will 
need to do both
a) --enable-nonportable-atomics
b) specify architecture as 486 with CFLAGS to override default of 386

> fwiw, I'm using gcc -O2 to get the inline attribute to kick in.  
> Regardless of what we do with the API, we should commit the inline 
> attribute IMO because it is a nearly free performance boost.

Inlining isn't going to help in the real world* since the implementation is 
hidden inside APR.  Hide your new add32 inside APR and performance is going to 
go south.

*except for helper functions used in the implementation of atomics, of course



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