Jenkins is downloading the whole host, how to find the problem?

Question

Jenkins

Host:
ec2 t2.medium: 2vcpu / 4 ram
ubuntu 18.04
openjdk 11.0.3 2019-04-16
Fat process search:
top -n1 -bH -o %CPU -p 2492 | head -n2
2 processes that load the host:

PID USER      PR  NI    VIRT    RES    SHR S %CPU %MEM     TIME+ COMMAND
 2495 jenkins   20   0 3866180 1.362g  29772 R 84.2 35.4   9:12.84 GC Thread#0
 2510 jenkins   20   0 3866180 1.362g  29772 R 84.2 35.4   9:14.47 GC Thread#1

Tried to increase heap, but nothing changed
JAVA_ARGS="-Xmx1048m -XX:MaxPermSize=512m"
How to debug GC?

Answer 1

does this happen when doing jobs or just when jenkins server is running?