Extending ThreadCPULoadEvent functionality? (discussion)

[Jaroslav Bachorík]

Hello,

in its current form the ThreadCPULoadEvent converts the collected CPU
time into (estimated) CPU load and does this only for Java threads.

It would be extremely useful (at least to us in Datadog) to have
access to the raw CPU time which was used to calculate the load.
Although we can kind of reverse-engineer that from the wall time and
the reported number of CPUs it is awkward and in case of containerized
environments might not be very precise.
As for the thread cpu load events emitted for non-java thread - this
would be mostly useful for attributing the overall load to
java/non-java threads which in turn allows for making conclusion about
user load vs. the runtime load eg.

The idea proposed here is to capture the CPU time as an event
attribute and do that for both java and non-java thread,
distinguishing between them via another event attribute.

The code changes are very PoC - the code does what it is supposed to
do without causing any regressions but the actual implementation is
subject to change depending on the outcomes of this discussion.

Webrev: http://cr.openjdk.java.net/~jbachorik/jfr_cpu_time/webrev/

Thanks all for taking your time here!

Cheers,

-JB-