Java APM agent not pushing CPU & Memory metric - IBM Java on WebSphere Liberty

felixbarny · April 17, 2020, 1:42pm

I think I know why capturing the CPU metrics doesn't work. The IBM-specific MBean behaves slightly differently than the Sun-specific one:

https://www.ibm.com/support/knowledgecenter/SSYKE2_8.0.0/com.ibm.java.api.80.doc/com.ibm.lang.management/com/ibm/lang/management/OperatingSystemMXBean.html#getSystemCpuLoad--
https://www.ibm.com/support/knowledgecenter/SSYKE2_8.0.0/com.ibm.java.api.80.doc/com.ibm.lang.management/com/ibm/lang/management/OperatingSystemMXBean.html#getSystemCpuLoad--

The first call to the method always returns CpuLoadCalculationConstants .ERROR_VALUE (-1.0), which marks the starting point.

However, we treat -1 a not available on this platform and don't register the metric. That should be an easy fix here:

github.com

elastic/apm-agent-java/blob/96b7d60e4edcb39242ab5d7922111d52fd9c1023/apm-agent-core/src/main/java/co/elastic/apm/agent/metrics/builtin/SystemMetrics.java#L102-L114


      
          metricRegistry.addUnlessNegative("system.cpu.total.norm.pct", Labels.EMPTY, new DoubleSupplier() {
              @Override
              public double get() {
                  return invoke(systemCpuUsage);
              }
          });
          
          metricRegistry.addUnlessNegative("system.process.cpu.total.norm.pct", Labels.EMPTY, new DoubleSupplier() {
              @Override
              public double get() {
                  return invoke(processCpuUsage);
              }
          });

Are you interested in providing a PR for this?

Regarding the Memory graph, there seems to be an inconsistency of what's returned from getTotalPhysicalMemorySize and what's in /proc/meminfo. Could you send me the output of cat /proc/meminfo?

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Java APM agent not pushing CPU & Memory metric - IBM Java on WebSphere Liberty

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