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6670与6678 FFT效率对比



请问一下6670的FFTC单元对256*256大小的矩阵做快速傅里叶变化要多少时间,6678又需要多少时间?

 我看到一个文档中说如下图的性能参数,我想问问如果用6670 4核+FFTC 性能参数又是多少呢?比如说64K大小的数据用FFTC的计算时间是多少呢?谢谢!

  • 您好,

    (1) 6670有3个FFTC, 一般是用于LTE系统中的。关于FFTC的运算能力您可以参考FFTC user guide: www.ti.com/.../sprugs2c.pdf

    6670有4个核,用核本身就是可以计算FFT的,可参考其datasheet中Mac运算的能力:“38.4 GMacs/Core for Fixed Point @ 1.2 GHz”,即工作在1.2GHz时,每个核每秒可做38.4G次MAC运算。

    (2) 6678没有FFTC,但它有8个核,从datasheet上可看,“40 GMAC/Core for Fixed Point @ 1.25 GHz”,即工作在1.25GHz时,每个核每秒可做40G次MAC运算。

     

    虽然mac运算能力两芯片有不同,但由于不确定您使用芯片时核和FFTC的配置,所以暂时无法对比效率。

  • 您好,请在同一个帖子中追加提问比较好,直接在回帖下面继续回复就行了。

    关于您的文档,您能提供文档全文吗?

  • 您好,文档如附件第四页

    Exp5_VLFFT.pdf
  • 另外在附件文档1 KeyStone Architecture FFTC.pdf  第16页中提到:

    The memory buffer of the FFT engine is divided into three banks. Each bank can hold

    a maximum of 4096 FFT words. Each complex FF T input sample is made up of a 16-bit

    real and 16-bit imaginary part. The engine  performs its computations in-place. The

    purpose of the three banks is to allow the  system to read from one bank, write to

    another while the engine is pr ocessing the data in the third when the FFT sizes are not

    more that 4096. For FFT sizes 6144 and 8192, two of the three banks are used and

    therefore simultaneous reading and writing  of data cannot be performed while the

    engine is processing data.

    是不是FFTC不支持大于8192大小的傅里叶计算呢?

    还有我对FFTC的用途还是不是很明确,文档中说它是用于LTE,其他的用途可以吗?

    我现在要做的是一个256*256大小的图像复原,算法中有一个循环迭代的过程,在循环内部有多次FFT,对于我的用途TTFC能否起到作用?我的系统对实时性要求非常高,要至少达到毫秒级,初步计算要300次FFT,请问用6670或者6678能否满足要求呢?

    KeyStone Architecture FFTC.pdf