[FFmpeg-devel] [PATCH] avutil/avstring: Inline some tiny functions

Ganesh Ajjanagadde gajjanag at mit.edu
Sat Sep 26 19:23:10 CEST 2015


On Sat, Sep 26, 2015 at 1:18 PM, Hendrik Leppkes <h.leppkes at gmail.com> wrote:
> On Sat, Sep 26, 2015 at 6:48 PM, Ganesh Ajjanagadde <gajjanag at mit.edu> wrote:
>> On Sat, Sep 26, 2015 at 12:26 PM, Henrik Gramner <henrik at gramner.com> wrote:
>>> On Sat, Sep 26, 2015 at 6:10 PM, Ganesh Ajjanagadde <gajjanag at mit.edu> wrote:
>>>> Have you compared with av_always_inline?
>>>
>>> No, other functions in that header used "inline", so I went with the
>>> same for consistency. But I guess we could change those as well if
>>> av_always_inline is preferable.
>>
>> Commit  06eb4f0885746b7e8a652d7b6026abf834e04b73 has a fairly detailed
>> explanation of av_always_inline. Essentially the question is: do we
>> trust the compiler to do the right thing here? In the worst case, the
>> compiler will not inline it, in which case what is the performance
>> penalty?
>> My suspicion is that the loss is not that bad, and since there is no
>> inline asm, the compiler in all likelihood won't need the
>> av_always_inline.
>>
>> Thus either one should be ok (pick whichever you prefer), and so LGTM.
>
> The functions were not inline before, so there is no "penality", and only gain.
> For consistency, picking normal inline should be preferred here.

I meant penalty when comparing inline vs av_always_inline, and not
current vs proposed patch.
Anyway, patch is fine.

>
> - Hendrik
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