compiler monitorig/tuning

Brian Toal brian.toal at
Thu Jun 16 18:00:42 UTC 2016

Good day,

- How do I monitor the length of the compiler queues (client and server)?
I want to understand the backlog (if any) to determine if the application
could benefit from more compilation threads.

- I remember in the past being able to get detailed compiler statistics
from a mbean or something where the metric was prefixed with and it
contained execution count, total time, thread count exec for the client and
server compilers.  Where can I find this data in realtime for monitoring
purposes?  If I know the total time and thread count I suppose I can work
out if the utilization of the compilation threads.

- What other compilation metrics should I be paying close attention to?

- Other than tiered compilation becoming the default in Java 8, where there
any significant changes that would have slowed down compilation time?
We've had -XX:-TieredCompilation set in Java 7 and 8 and haven't touched
any other JIT related config.  Was there some other setting default that
changed which we would have needed to change when going fro 7 to 8?
Looking at the various compiler parameters that I know about via
PrintFlagsFinal from 7 and 8, there doesn't seem to be any change other
than -XX:-TieredCompilation.

- Brian
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