Java agent cause high CPU usage

[happyycm]

Search before asking

• I had searched in the issues and found no similar issues.

Apache SkyWalking Component

Java Agent (apache/skywalking-java)

What happened

Java agent cause high CPU usage for a long time。
Process ”SkywalkingAgent“ Take up to 80% CPU

What you expected to happen

Process ”SkywalkingAgent“ Take up to 80% CPU for a long time.

How to reproduce

"SkywalkingAgent-5-JVMService-consume-0" #8 daemon prio=5 os_prio=0 tid=0x00007fd6c47e0800 nid=0x10 runnable [0x00007fd69f278000] java.lang.Thread.State: TIMED_WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x00000000c0061bb0> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject) at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215) at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2078) at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:1093) at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:809) at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at java.lang.Thread.run(Thread.java:748)

Anything else

No response

Are you willing to submit PR?

• Yes I am willing to submit a PR!

Code of Conduct

• I agree to follow this project's Code of Conduct

[Cool-Coding]

@happyycm In my opinion, when a thread parks, it won't occupy cpu. Can you provide more detailed information or tell us how to reproduce this?

[happyycm]

From the thread id,can trace to the code from "org.apache.skywalking.apm.agent.core.jvm.JVMService"

Executors.newSingleThreadScheduledExecutor( new DefaultNamedThreadFactory("JVMService-produce")) .scheduleAtFixedRate(new RunnableWithExceptionProtection( this, new RunnableWithExceptionProtection.CallbackWhenException() { @Override public void handle(Throwable t) { LOGGER.error("JVMService produces metrics failure.", t); } } ),

......
`@Override
public void run() {
long currentTimeMillis = System.currentTimeMillis();
try {
JVMMetric.Builder jvmBuilder = JVMMetric.newBuilder();
jvmBuilder.setTime(currentTimeMillis);
jvmBuilder.setCpu(CPUProvider.INSTANCE.getCpuMetric());
jvmBuilder.addAllMemory(MemoryProvider.INSTANCE.getMemoryMetricList());
jvmBuilder.addAllMemoryPool(MemoryPoolProvider.INSTANCE.getMemoryPoolMetricsList());
jvmBuilder.addAllGc(GCProvider.INSTANCE.getGCList());
jvmBuilder.setThread(ThreadProvider.INSTANCE.getThreadMetrics());
jvmBuilder.setClazz(ClassProvider.INSTANCE.getClassMetrics());

        sender.offer(jvmBuilder.build());
    } catch (Exception e) {
        LOGGER.error(e, "Collect JVM info fail.");
    }
}, `

report the JVM Metric data per seconds.
will this cause high CPU usage?

[wu-sheng]

Diagnosis is not community's responsibility. You need to do research first. Moving to the discussion.