[FFmpeg-devel] [PATCH] split mpegvideo.c

[Benoit Fouet]

Michael Niedermayer wrote:
> Hi
>
> On Mon, Jul 02, 2007 at 12:18:21PM +0200, Benoit Fouet wrote:
>   
>> Hi,
>>
>> Michael Niedermayer wrote:
>>     
>>> Hi
>>>
>>> On Thu, Jun 28, 2007 at 01:38:23PM +0200, Benoit Fouet wrote:
>>>   
>>>       
>>>> Benoit Fouet wrote:
>>>>     
>>>>         
>>>>> M?ns Rullg?rd wrote:
>>>>>   
>>>>>       
>>>>>           
>>>>>> Benoit Fouet <benoit.fouet at purplelabs.com> writes:
>>>>>>   
>>>>>>     
>>>>>>         
>>>>>>             
>>>>>>> Hi,
>>>>>>>
>>>>>>> here is a first attempt to $subj
>>>>>>>
>>>>>>> what is done:
>>>>>>>  - remove everything flagged under CONFIG_ENCODERS from mpegvideo.c
>>>>>>> (apart from the DCT_common_init() part)
>>>>>>>  - put those parts in mpegvideo_enc.c
>>>>>>>     
>>>>>>>       
>>>>>>>           
>>>>>>>               
>>>>>> Does this in any way affect performance?  I can imagine calls from
>>>>>> encoding functions to common functions no longer being inlined due to
>>>>>> the split.  Then again, there might not be any relevant such calls.
>>>>>>
>>>>>>   
>>>>>>     
>>>>>>         
>>>>>>             
>>>>> i didn't check performances yet. but this is a problem we might have, i
>>>>> guess...
>>>>>
>>>>>   
>>>>>       
>>>>>           
>>>> anyway, what would be the proper way to do such a benchmark.
>>>> As it is something i never did in ffmpeg, any pointer on how to do it
>>>> would be very welcome !
>>>>     
>>>>         
>>> nm anychangedobject.o
>>>
>>> and checking if new function names appear (simply cleaning the output of nm
>>> with sed and diffing them works well), if so they are no longer inlined
>>> (this will tell us what needs benchmarking)
>>>
>>>   
>>>       
>> ok, i did that.
>> it seems the only differences are the following ones:
>>  - copy_picture is now defined
>>  - MPV_common_defaults too
>>
>> the two of them were implicitely inlined by the compiler actually.
>> i think copy_picture could be moved to the common header file to make it
>> inlined again, but this should not be necessary for
>> MPV_commmon_defaults, which is only called at initialization of codec.
>>     
>
> neither of the 2 should be inlined, so theres no need to move them into
> header
>
> [...]
>   
ok

does that mean i have to benchmark calls to copy_picture or that the
patch can be applied ?
-- 
Ben
Purple Labs S.A.
www.purplelabs.com