System and Process + Kernel CPU usage estimates stuck at 100

Questions about YourKit Java Profiler
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johnmuller71
Posts: 1
Joined: Tue Dec 01, 2020 5:52 pm

System and Process + Kernel CPU usage estimates stuck at 100

Post by johnmuller71 »

We are running YourKit 2020.9 and remote profiling a Java application hosted inside a Linux Docker container. Checking /proc/stat and top shows that our CPU has idle time, and is usually sitting at around 60-70% usage.

We used the guide https://www.yourkit.com/docs/java/help/docker.jsp to setup our Dockerfile and have no special options enabled, everything default.

When attached to the remote agent, it shows constant 100% CPU usage. System is at 100% and Process + Kernel is at 100% always for the entire duration of the session.

Image

This is definitely incorrect, is there any way to fix this or improve the accuracy of the estimate?

Thanks.
Anton Katilin
Posts: 6172
Joined: Wed Aug 11, 2004 8:37 am

Re: System and Process + Kernel CPU usage estimates stuck at

Post by Anton Katilin »

Hello,

It's a new issue.

What processor count is shown in the "Summary" tab, in the "Operating System" section?
Does it match the actual number?

Could you please send to [email protected] the following:
- the profiler agent log file <user home>/.yjp/log/<session name>-<pid>.log
- a performance snapshot file demonstrating the problem
- "uname -a" output of the host
- "uname -a" inside the container.
Anton Katilin
Posts: 6172
Joined: Wed Aug 11, 2004 8:37 am

Re: System and Process + Kernel CPU usage estimates stuck at

Post by Anton Katilin »

Update:

The problem was caused by using particular OpenJDK version which incorrectly reported the processor count.

The problem was solved by using another OpenJDK version (namely, from https://hub.docker.com/r/adoptopenjdk/openjdk8).
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