* commit 'f963f80399deb1a2b44c1bac3af7123e8a0c9e46':
arm: Use .data.rel.ro for const data with relocations
Conflicts:
configure
Merged-by: Michael Niedermayer <michaelni@gmx.at>
* commit 'b280c6202b28b371a8d96850194fd69d7ad5dcc0':
arm: fft_vfp: Unify the behaviour in ff_fft_calc_vfp between arm/thumb
Merged-by: Michael Niedermayer <michaelni@gmx.at>
* commit 'ae81576414f2d2083d3118fb4abe1ebc5a7a4c54':
arm: fft_vfp: Add a missing "endconst" when building in thumb mode
Merged-by: Michael Niedermayer <michaelni@gmx.at>
Don't include the function pointer table in the code segment
in arm mode.
This shouldn't have any significant performance effect. It does
end up as a few more instructions than before, for ARM, but
only at the entry to this function, not within the fft functions
themselves.
Signed-off-by: Martin Storsjö <martin@martin.st>
* commit '87552d54d3337c3241e8a9e1a05df16eaa821496':
armv6: Accelerate ff_fft_calc for general case (nbits != 4)
Merged-by: Michael Niedermayer <michaelni@gmx.at>
The previous implementation targeted DTS Coherent Acoustics, which only
requires nbits == 4 (fft16()). This case was (and still is) linked directly
rather than being indirected through ff_fft_calc_vfp(), but now the full
range from radix-4 up to radix-65536 is available. This benefits other codecs
such as AAC and AC3.
The implementaion is based upon the C version, with each routine larger than
radix-16 calling a hierarchy of smaller FFT functions, then performing a
post-processing pass. This pass benefits a lot from loop unrolling to
counter the long pipelines in the VFP. A relaxed calling standard also
reduces the overhead of the call hierarchy, and avoiding the excessive
inlining performed by GCC probably helps with I-cache utilisation too.
I benchmarked the result by measuring the number of gperftools samples that
hit anywhere in the AAC decoder (starting from aac_decode_frame()) or
specifically in the FFT routines (fft4() to fft512() and pass()) for the
same sample AAC stream:
Before After
Mean StdDev Mean StdDev Confidence Change
Audio decode 2245.5 53.1 1599.6 43.8 100.0% +40.4%
FFT routines 940.6 22.0 348.1 20.8 100.0% +170.2%
Signed-off-by: Martin Storsjö <martin@martin.st>
Before After
Mean StdDev Mean StdDev Change
This function 1389.3 4.2 967.8 35.1 +43.6%
Overall 15577.5 83.2 15400.0 336.4 +1.2%
Signed-off-by: Martin Storsjö <martin@martin.st>
Michael Niedermayer
Martin Storsjö
Ben Avison