- 09 Dec, 2014 1 commit
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Martin Storsjö authored
Signed-off-by: Martin Storsjö <martin@martin.st>
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- 08 Dec, 2014 2 commits
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Martin Storsjö authored
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>
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Martin Storsjö authored
Signed-off-by: Martin Storsjö <martin@martin.st>
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- 17 Jul, 2014 1 commit
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Ben Avison authored
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>
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- 22 Jul, 2013 1 commit
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Martin Storsjö authored
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>
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