Hi,

  Thanks for your time!

I am bob. I am interested in the CoreSight Project. And I get much from the web page http://www.linaro.org/blog/core-dump/coresight-perf-and-the-opencsd-library/.

Because I work on ARM64, there is a bug with perf working on ARM. Specific information from https://www.linaro.org/blog/core-dump/debugging-arm-kernels-using-nmifiq/.

  For instance, when we run : dd if=/dev/urandom of=/dev/null, over 90% of the CPU time is spent unlocking interrupts and the cryptographic operations that should dominate the

use case are completely hidden.

The author Daniel Thompson from Linaro comes up with a primary solution, however he suggests it will need further work.

Now, CoreSight can trace program flow only by hardware. If we combine coresight with perf, when we run “dd if=/dev/urandom of=/dev/null” and perf record, will the report be normal?   

  If it is normal, it will be amazing!!! And, I am eager for the related information.

  I have followed the documentation to enable coresight and perf, but get stuck. I can not figure out whether it is normal.

  I greatly appreciate for your help!!!    Thanks again for your time!!!