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EM 13.4: OMS Java Process Consuming High CPU and Causing Console Slowness / OMS Hung Intermittently (Doc ID 2702019.1)

Last updated on SEPTEMBER 13, 2023

Applies to:

Enterprise Manager Base Platform - Version and later
Information in this document applies to any platform.


This issue can happen after upgrading the EM to 13.4 or in a new installation of EM 13.4

1. OMS java process is consuming high amount CPU usage intermittently.

2. During this time, users may observe console slowness. 

3. $../gc_inst/em/EMGC_OMS1/sysman/log/emctl.log may report the following errors too:

[main] ERROR oms.StatusOMSCmd processStatusOMS.360 - Exception when trying to hit OMS page. Read timed out


$../gc_inst/user-projects/domains/GCDomain/servers/EMGC_OMS1/logs/EMGC_OMS1*.out* file may report following errors:

Java HotSpot(TM) 64-Bit Server VM warning: CodeCache is full. Compiler has been disabled.
Java HotSpot(TM) 64-Bit Server VM warning: Try increasing the code cache size using -XX:ReservedCodeCacheSize=
CodeCache: size=102400Kb used=101070Kb max_used=101207Kb free=1329Kb
bounds [0x00007f22c1c00000, 0x00007f22c8000000, 0x00007f22c8000000]
total_blobs=19338 nmethods=17539 adapters=1700
compilation: disabled (not enough contiguous free space left)

 4. ReservedCodeCache will be nearly 100% full. This can be verified from:

5.  From the thread dumps which are collected at the time of issue, JVM compiler threads are causing the high CPU.

This can be verified from the following steps:

5.1) Identify the OMS PID using following command

$ps -ef | grep EMGC_OMS1

$MW_HOME/oracle_common/jdk/bin/jstack <OMS PID> > /tmp/oms1_jstack.txt

5.2) Collect CPU usage of OMS threads

$ps -C java -L -o pcpu,cpu,nice,state,cputime,pid,tid | grep <OMS_PID> > /tmp/oms1_thred_cpu.txt

5.3) Convert hexadecimal nid to decimal

Search for "Compiler" key word to locate compiler threads in /tmp/oms1_jstack.txt
There will be multiple compiler threads.
Convert it's nid value from hexadecimal to decimal.

5.4) Find the cpu utilisation of compiler threads

Search for decimal nid value in /tmp/oms1_thred_cpu.txt
First column shows the CPU utilisation
Repeat the above 2 steps for remaining compiler nids


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