Abnormal high sys time in G1 GC

[Thomas Schatzl]

Hi,

On 20.01.20 11:51, Bernd Eckenfels wrote:
> Hello,
> 
> Can you say a bit what's the actual problem? Your smys times in those 
> GCs look large, but it's only a 4s Pause for a 160gb heap. I am sure you 

In my experience, 4s pause for a 160gb heap is rather unusual and 
unexpected particularly on a young-only collection. Even on jdk8 (later 
jvms are much better), but it certainly depends on application.

> saw that pause time before? I think it's pretty hard to tell after the 
> fact, but with such a large system I would lean towards problems outside 
> of the JVM.

According to https://access.redhat.com/solutions/46111 you can get 
statistics about THP activity looking at /proc/<pid>/vmstat.

This looks just like one of these one-off occurrences THP could cause.

Thanks,
   Thomas