Cycle counter on TX2? Like FFTW's cycle.h

Hello TX2 developers. For years I have been using the cycle.h timing code included as part of the FFTW 3 source code. It has worked flawlessly across devices and platforms. However when compiled on the TX2 it cannot detect any support for a cycle counter, even when there is ARMv8 support on the code.
(The tests for HAVE_ARMV8_PMCCNTR_EL0 and HAVE_ARMV8_CNTVCT_EL0 both fail).

This has been confirmed by compiling fftw 3.3.8 from source, which warns that fftw plans will be “estimated” instead.

I was wondering if the community had an alternative cycle counter while running on the TX2. Maybe we can augment the cycle.h with Tegra support?

Thanks for any insights.

Could you have more detail like how to use FFTW and what the failed message got.