c1/c2 compiler thread eats a lot of cpu

[Aleksey Shirokih]

hi.

My JIRA instalation eats alot of cpu time during "not so high load" at night for example.

thread dump shows that most of the time that threads are on

"C1 CompilerThread3" #8 daemon prio=9 os_prio=0 tid=0x00007f534400a800 nid=0x56d3 runnable [0x0000000000000000]

   java.lang.Thread.State: RUNNABLE

"C2 CompilerThread2" #7 daemon prio=9 os_prio=0 tid=0x00007f5344008800 nid=0x56d2 waiting on condition [0x0000000000000000]

   java.lang.Thread.State: RUNNABLE

"C2 CompilerThread1" #6 daemon prio=9 os_prio=0 tid=0x00007f5344006800 nid=0x56d1 waiting on condition [0x0000000000000000]

   java.lang.Thread.State: RUNNABLE

"C2 CompilerThread0" #5 daemon prio=9 os_prio=0 tid=0x0000000001eb3000 nid=0x56d0 waiting on condition [0x0000000000000000]

   java.lang.Thread.State: RUNNABLE

any ideas how to debug it?

 one.PNG

[Matheus Fernandes · Accepted solution]

Hi, Aleksey,

May I know if can see the following on the JIRA logs:

Java HotSpot(TM) 64-Bit Server VM warning: CodeCache is full. Compiler has been disabled.

I believe this may be related to the CompilerThreads using so much CPU. This behavior is fully explained on this blog post:

We don’t have any statistics as to the impact of this on long running performance; the impression that I have is that CPU utilisation & request service time would increase over long running VMs for code that could have been optimised. For a system that is over-committed on CPU resources the application throughput could decrease noticeably.

To try to mitigate that, could you try adding the following parameters to the JIRA startup and restart JIRA:

• -XX:ReservedCodeCacheSize=384m
• -XX:+UseCodeCacheFlushing
  ^{Reference: https://confluence.atlassian.com/x/6xS_Eg}

I hope this helps!

[Aleksey Shirokih]

adding that two options helps. tnx