cufft中由于数据大小影响速度的问题

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The cuFFT product supports a wide range of FFT inputs and options efficiently on NVIDIA GPUs. This version of the cuFFT library supports the following features:

Algorithms highly optimized for input sizes that can be written in the form 2 a × 3 b × 5 c × 7 d . In general the smaller the prime factor, the better the performance, i.e., powers of two are fastest.
最近发现傅立叶变换速度太慢，查看cuda文档中有这样一段话，但是我实际数据量并不是2的n次方，那么我应该怎么做呢