[FFmpeg-devel] [PATCH] Altivec version of h264_idct_add

[David Conrad]

On Jun 1, 2007, at 7:36 PM, Michael Niedermayer wrote:

> Hi
>
> On Fri, Jun 01, 2007 at 06:52:57PM -0400, David Conrad wrote:
>> Hi,
>>
>> This is an updated version of ff_h264_idct_add_altivec, based on a
>> patch by Mauricio Alvarez [1]. It's 1.9 times faster than the scalar
>> version on my G4. Regression tests pass except for seektest, which is
>> currently broken for me with vanilla SVN (should it work?)
>>
>> 170 dezicycles in ff_h264_idct_add_altivec, 1 runs, 0 skips
>> 150 dezicycles in ff_h264_idct_add_altivec, 2 runs, 0 skips
>> 287 dezicycles in ff_h264_idct_add_altivec, 4 runs, 0 skips
>> 203 dezicycles in ff_h264_idct_add_altivec, 8 runs, 0 skips
>> 131 dezicycles in ff_h264_idct_add_altivec, 16 runs, 0 skips
>> 79 dezicycles in ff_h264_idct_add_altivec, 32 runs, 0 skips
>> 53 dezicycles in ff_h264_idct_add_altivec, 64 runs, 0 skips
>> 33 dezicycles in ff_h264_idct_add_altivec, 128 runs, 0 skips
>> 23 dezicycles in ff_h264_idct_add_altivec, 256 runs, 0 skips
>> 18 dezicycles in ff_h264_idct_add_altivec, 512 runs, 0 skips
>> 15 dezicycles in ff_h264_idct_add_altivec, 1024 runs, 0 skips
>> 14 dezicycles in ff_h264_idct_add_altivec, 2048 runs, 0 skips
>> 14 dezicycles in ff_h264_idct_add_altivec, 4096 runs, 0 skips
>> 13 dezicycles in ff_h264_idct_add_altivec, 8192 runs, 0 skips
>> 14 dezicycles in ff_h264_idct_add_altivec, 16384 runs, 0 skips
>> 14 dezicycles in ff_h264_idct_add_altivec, 32768 runs, 0 skips
>> 14 dezicycles in ff_h264_idct_add_altivec, 65536 runs, 0 skips
>
> where where the START/STOP_TIMER placed?
> this doesnt look correct the idct isnt being executed in 1.4 cpu  
> cycles

Like so:

static void ff_h264_idct_add_altivec(...)
{
     START_TIMER
     vec_s16_t va0, va1, va2, va3;
[...]
         VEC_LOAD_U8_ADD_S16_STORE_U8(dst,va3,dstperm);
     }
     STOP_TIMER("ff_h264_idct_add_altivec")
}

It's my first time using these macros; where should they be?