Designing SOCs with Configured Cores

14.9. Alone, Faster is Not Necessarily Better

The above examples demonstrate that application-tailored processors can run specific code blocks one or two orders of magnitude faster than fixed-ISA processors without the need for faster clock rates. However, most SOCs also require that power dissipation and energy consumption (power dissipated over time) not rise commensurately with the performance improvement. Here too, configurable processors excel. Figure 14.4 demonstrates the performance and power benefits of application tailoring for three applications: AES (advanced encryption standard) cryptographic coding and decoding, Viterbi decoding, and the FFT. In each case, ISA extensions have been added to an Xtensa processor to improve its performance. ...