Adds a new section to the host profiles that includes JVM GC related
metrics. These metrics are taken from JMX and the JvmPauseMonitor.
The host profiles will now include a section like below:
JVM:
- GcCount: 19
- GcNumInfoThresholdExceeded: 0
- GcNumWarnThresholdExceeded: 0
- GcTimeMillis: 17s476ms
- GcTotalExtraSleepTimeMillis: 380
GcNumInfoThresholdExceeded, GcNumWarnThresholdExceeded, and
GcTotalExtraSleepTimeMillis are all taken from JvmPauseMonitor.
GcCount and GcTimeMillis are taken from JMX (specifically,
GarbageCollectorMXBean).
The counters themselves are derived from the impalad host-level metrics.
Changed the 'lock_' in JvmMetricCache (in memory-metrics.h) from a mutex
to a shared_mutex. Most accessors of the JvmMetricCache member variables
are read-only. A write only occurs lazily at most every second. This
should help reduce lock contention on JvmMetricCache now that all
queries will start accessing info stored by the JvmMetricCache.
Testing:
* Ran core tests
* Added a test that runs Java UDF, which triggers JVM GC
Change-Id: Idbaae2f9142b8be94532a0a147668a3d96091b0b
Reviewed-on: http://gerrit.cloudera.org:8080/16414
Reviewed-by: Tim Armstrong <tarmstrong@cloudera.com>
Reviewed-by: Sahil Takiar <stakiar@cloudera.com>
Tested-by: Sahil Takiar <stakiar@cloudera.com>
