# FFT 性能测试 ## 概述 fft性能测试主要测试了DSP、ffa以及软件进行fft和ifft变换的性能，包含如下计算单元 - DSP FFT-RADIX-2 - DSP FFT-RADIX-4 - DSP IFFT-RADIX-4 - DSP IFFT-RADIX-2 - DSP FFT-RADIX-2 Q31 - CPU Cooley-Tukey算法 - Q格式和float32互转 ## 程序设计 软件生成生成几个幅值和相位不同的正弦波并叠加生成一个波形，然后使用fft变换求出幅频特性数据，最后做ifft回复原始数据， 并比对ifft的数据和fft变换的数据是否相一致。几个正弦波如下所示: - 幅值11，频率8 - 幅值19，频率17 - 幅值13，频率24 ## 硬件设置 无特殊设置 ## 性能优化 - segger已经默认开启O3优化 - hpm_math默认开启了对CPU Cooley-Tukey算法的计算优化，会增加空间占用 ## 运行现象 当工程正确运行后，串口终端会输出计算的名称，采样点数，以及幅频特性的数据，以及每一个单元的运行时间，并在最后输出PASS或者ERROR NUM. 串口输出如下所示： ```console dsp fft radix-4 Total samples: 64. total times:5813 tick. ------------------------------------ DC component amplitude:10.000006. Frequency:8.000000, Amplitude:11.000008. Frequency:17.000000, Amplitude:18.999988. Frequency:24.000000, Amplitude:23.000000. ------------------------------------ dsp ifft radix-4 Total samples: 64. total times:5961 tick. ------------------------------------ dsp fft radix-4 Total samples: 256. total times:29671 tick. ------------------------------------ DC component amplitude:9.999996. Frequency:8.000000, Amplitude:11.000002. Frequency:17.000000, Amplitude:18.999998. Frequency:24.000000, Amplitude:23.000003. ------------------------------------ dsp ifft radix-4 Total samples: 256. total times:30220 tick. ------------------------------------ dsp fft radix-4 Total samples: 1024. total times:144992 tick. ------------------------------------ DC component amplitude:9.999997. Frequency:8.000000, Amplitude:11.000000. Frequency:17.000000, Amplitude:19.000000. Frequency:24.000000, Amplitude:23.000000. ------------------------------------ dsp ifft radix-4 Total samples: 1024. total times:147161 tick. ------------------------------------ ************************************** dsp fft radix-2 Total samples: 64. total times:9280 tick. ------------------------------------ DC component amplitude:10.000006. Frequency:8.000000, Amplitude:11.000008. Frequency:17.000000, Amplitude:18.999988. Frequency:24.000000, Amplitude:23.000000. ------------------------------------ dsp ifft radix-2 Total samples: 64. total times:9544 tick. ------------------------------------ dsp fft radix-2 Total samples: 128. total times:21119 tick. ------------------------------------ DC component amplitude:9.999998. Frequency:8.000000, Amplitude:11.000001. Frequency:17.000000, Amplitude:18.999996. Frequency:24.000000, Amplitude:23.000003. ------------------------------------ dsp ifft radix-2 Total samples: 128. total times:21575 tick. ------------------------------------ dsp fft radix-2 Total samples: 256. total times:47643 tick. ------------------------------------ DC component amplitude:9.999996. Frequency:8.000000, Amplitude:11.000002. Frequency:17.000000, Amplitude:19.000000. Frequency:24.000000, Amplitude:23.000003. ------------------------------------ dsp ifft radix-2 Total samples: 256. total times:48582 tick. ------------------------------------ dsp fft radix-2 Total samples: 512. total times:106047 tick. ------------------------------------ DC component amplitude:9.999997. Frequency:8.000000, Amplitude:11.000000. Frequency:17.000000, Amplitude:19.000000. Frequency:24.000000, Amplitude:22.999998. ------------------------------------ dsp ifft radix-2 Total samples: 512. total times:108005 tick. ------------------------------------ dsp fft radix-2 Total samples: 1024. total times:234172 tick. ------------------------------------ DC component amplitude:9.999997. Frequency:8.000000, Amplitude:11.000000. Frequency:17.000000, Amplitude:19.000000. Frequency:24.000000, Amplitude:23.000000. ------------------------------------ dsp ifft radix-2 Total samples: 1024. total times:237975 tick. ------------------------------------ ************************************** dsp fft q31 radix-2 Total samples: 64. total times:3782 tick. ------------------------------------ DC component amplitude:10.000006. Frequency:8.000000, Amplitude:11.000009. Frequency:17.000000, Amplitude:18.999988. Frequency:24.000000, Amplitude:23.000000. ------------------------------------ dsp ifft q31 radix-2 Total samples: 64. total times:4220 tick. ------------------------------------ dsp fft q31 radix-2 Total samples: 128. total times:8252 tick. ------------------------------------ DC component amplitude:9.999998. Frequency:8.000000, Amplitude:11.000002. Frequency:17.000000, Amplitude:18.999996. Frequency:24.000000, Amplitude:23.000003. ------------------------------------ dsp ifft q31 radix-2 Total samples: 128. total times:9274 tick. ------------------------------------ dsp fft q31 radix-2 Total samples: 256. total times:17995 tick. ------------------------------------ DC component amplitude:9.999995. Frequency:8.000000, Amplitude:11.000002. Frequency:17.000000, Amplitude:19.000000. Frequency:24.000000, Amplitude:23.000005. ------------------------------------ dsp ifft q31 radix-2 Total samples: 256. total times:20619 tick. ------------------------------------ dsp fft q31 radix-2 Total samples: 512. total times:39039 tick. ------------------------------------ DC component amplitude:9.999995. Frequency:8.000000, Amplitude:11.000001. Frequency:17.000000, Amplitude:19.000000. Frequency:24.000000, Amplitude:23.000000. ------------------------------------ dsp ifft q31 radix-2 Total samples: 512. total times:45407 tick. ------------------------------------ dsp fft q31 radix-2 Total samples: 1024. total times:85195 tick. ------------------------------------ DC component amplitude:9.999995. Frequency:8.000000, Amplitude:11.000002. Frequency:17.000000, Amplitude:19.000003. Frequency:24.000000, Amplitude:23.000001. ------------------------------------ dsp ifft q31 radix-2 Total samples: 1024. total times:99603 tick. ------------------------------------ ************************************** Software fft cooley tukey Total samples: 64. total times:14493 tick. ------------------------------------ DC component amplitude:10.000006. Frequency:8.000000, Amplitude:11.000014. Frequency:17.000000, Amplitude:18.999998. Frequency:24.000000, Amplitude:23.000019. ------------------------------------ Software fft cooley tukey Total samples: 128. total times:29009 tick. ------------------------------------ DC component amplitude:9.999998. Frequency:8.000000, Amplitude:11.000004. Frequency:17.000000, Amplitude:19.000003. Frequency:24.000000, Amplitude:23.000015. ------------------------------------ Software fft cooley tukey Total samples: 256. total times:61116 tick. ------------------------------------ DC component amplitude:9.999996. Frequency:8.000000, Amplitude:11.000000. Frequency:17.000000, Amplitude:18.999998. Frequency:24.000000, Amplitude:23.000000. ------------------------------------ Software fft cooley tukey Total samples: 512. total times:131520 tick. ------------------------------------ DC component amplitude:9.999997. Frequency:8.000000, Amplitude:10.999999. Frequency:17.000000, Amplitude:19.000001. Frequency:24.000000, Amplitude:23.000000. ------------------------------------ Software fft cooley tukey Total samples: 1024. total times:285106 tick. ------------------------------------ DC component amplitude:9.999997. Frequency:8.000000, Amplitude:10.999997. Frequency:17.000000, Amplitude:19.000000. Frequency:24.000000, Amplitude:22.999996. ------------------------------------ ************************************** ------------------------------------ convert data from float to q31, nums:128. total times:3163 tick. convert data from q31 to float, nums:128. total times:1177 tick. ------------------------------------ ------------------------------------ convert data from float to q31, nums:256. total times:6225 tick. convert data from q31 to float, nums:256. total times:2325 tick. ------------------------------------ ------------------------------------ convert data from float to q31, nums:512. total times:12269 tick. convert data from q31 to float, nums:512. total times:4629 tick. ------------------------------------ ------------------------------------ convert data from float to q31, nums:1024. total times:24395 tick. convert data from q31 to float, nums:1024. total times:9237 tick. ------------------------------------ ------------------------------------ convert data from float to q31, nums:2048. total times:47949 tick. convert data from q31 to float, nums:2048. total times:18453 tick. ------------------------------------ PASS. ``` 性能如下表所示： | 采样点 | 64 | 128 | 256 | 512 | 1024 | |------------------|-------|-------|-------|--------|--------| | DSP radix-4（fpu） | 5900 | N | 29869 | N | 145366 | | DSP radix-2（fpu） | 9345 | 21220 | 47762 | 106211 | 234534 | | DSP radix-2（Q31） | 4378 | 9581 | 21177 | 46126 | 101331 | | FFAQ31 | 2729 | 4923 | 7769 | 18999 | N | | CPU（Cooley-Tukey） | 14495 | 29171 | 61176 | 131084 | 283441 | | DSP radix-4（fpu） | 6016 | N | 30384 | N | 147651 | | DSP radix-2（fpu） | 9558 | 21632 | 48733 | 108296 | 238775 | | DSP radix-2（Q31） | 4641 | 10301 | 22980 | 50645 | 111359 | | FFAQ31 | 2687 | 4898 | 9152 | 18956 | N | | Q31 to Float | 1208 | 2392 | 4757 | 9493 | 18965 | | Float to Q31 | 5517 | 10958 | 21970 | 44022 | 88055 |