[FFmpeg-devel] MPEG-2 Acceleration Refactor

Greg Hulands ghulands
Fri Jun 22 10:44:38 CEST 2007


Hi,
Michael Niedermayer wrote:
> Hi
>
> On Fri, Jun 22, 2007 at 09:08:23AM +0100, M?ns Rullg?rd wrote:
> [...]
>   
>> The inline keyword is nothing but a hint to the compiler that the
>> function might benefit from being inlined.  The compiler is free to
>> ignore it or to inline functions without it.  The final choice is
>> (ideally) that which makes the calling function faster.  Now if some
>> other function is forcibly inlined, the effect of inlining other
>> functions can quite reasonably be expected to change, just like had
>> more code been added to function body itself.  Expecting the decisions
>> whether to inline other function calls to be unaffected by this
>> addition of code doesn't seem quite rational to me.
>>     
>
> it does seem quite rational to me
> i want a attribute which behaves as if i copy and pasted the code or
> replaced it by a macro but without the source code duplication of the
> first and uglyness of \ at the end of each line of the second case
>
>   
I have attached the symbols from running the finline-limit=32768 as well 
as the original ones for comparison. If it turns out that the only 
solution is to go with a macro, would you have objections to that? It 
might be ugly, but if it is the only way to get the performance, then 
there isn't much of a choice. Or would the patch remain pending until 
gcc put in an attribute that does what is required? I hope the later is 
not the case.

I have said before that I'm out of my depth here, so I just want to try 
and get some clarification on this.

Does the current code that just have inline in the functions not 
inlining properly?

Is the av_always_inline behaving the same as inline or different?

Thanks,
Greg

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