How to profile high "system" cpu usage

Questions about YourKit Java Profiler
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ophir.salt
Posts: 2
Joined: Sun Oct 25, 2020 9:49 pm

How to profile high "system" cpu usage

Post by ophir.salt »

Hi,
I'm trying to profile JVM (scala) process. The cpu telemetry windows show a very high "system" cpu usage (up to 40%).
How can I dive deeper into the system cpu usage in order to figure out what's going on?
Also, and probably related - how can I see cpu usage on Java system calls such as reading from sockets and deciphering ssl?

Notes:
Profiling is done via cli (remote process, no UI).
Anton Katilin
Posts: 6172
Joined: Wed Aug 11, 2004 8:37 am

Re: How to profile high "system" cpu usage

Post by Anton Katilin »

Hi,

The profiler does not collect information about processes other than the process being profiled. The system CPU usage is obtained from the system as a number and shown as is, with no further detail. To see what other processes do on the system please use corresponding tools like "top".

For detail on the profiled JVM activities please use CPU profiling e.g. CPU sampling. I believe that the "Java system calls" you refer to happen inside the process being profiled and this is accounted to the process CPU usage. In the sampling results you'll see what calls use the CPU.

Important: since you are interested in CPU usage please consider measuring wall time for all methods when sampling: https://www.yourkit.com/docs/java/help/ ... ttings.jsp

Best regards,
Anton
ophir.salt
Posts: 2
Joined: Sun Oct 25, 2020 9:49 pm

Re: How to profile high "system" cpu usage

Post by ophir.salt »

Thank you!
Is there a way to change the wall time settings for an agent controlled by the cli?
Anton Katilin
Posts: 6172
Joined: Wed Aug 11, 2004 8:37 am

Re: How to profile high "system" cpu usage

Post by Anton Katilin »

Yes. Please see the "Configuration file" section:
https://www.yourkit.com/docs/java/help/ ... ttings.jsp
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