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. [cid:image003.jpg@01D1E8DF.C2B9E9D0]
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!!!
