JavaOOM_Non_JVM_Native_Code/OOM_Issues_Non_JVM_Native_Code at main · codeastra2/JavaOOM_Non_JVM_Native_Code · GitHub

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Author: srinivas1996kumar@gmail.com


We will be using JEMalloc, JeProf for tracking the increase in the memory in Non JVM Native code.

Useful References

https://technology.blog.gov.uk/2015/12/11/using-jemalloc-to-get-to-the-bottom-of-a-memory-leak/

https://blogs.oracle.com/poonam/troubleshooting-native-memory-leaks-in-java-applications
https://www.gnu.org/software/libc/manual/html_node/Malloc-Tunable-Parameters.html


Setting up dependencies
Add the required mirror: sudo yum-config-manager --add-repo=http://mirror.centos.org/centos/7/os/x86_64/
Vim into the file: sudo vi /etc/yum.repos.d/mirror.centos.org_centos_7_os_x86_64_.repo
Add the following line: gpgkey=http://mirror.centos.org/centos/7/os/x86_64/RPM-GPG-KEY-CentOS-7 gpgcheck=1
For installing gcc: sudo yum update && sudo yum group install "Development Tools"
Downloading jemalloc: wget https://github.com/jemalloc/jemalloc/releases/download/5.2.0/jemalloc-5.2.0.tar.bz2
Un-tar and enter directory: tar -xvf jemalloc-5.2.0.tar.bz2 && cd jemalloc-5.2.0.tar.bz2
Enable profiling: ./configure --enable-prof
Installing Jemalloc,Jeprof: make && sudo make install
Installation of visulization tools: sudo yum install ghostscript (For getting result in PDF format)


Configuring and using Jemalloc
Adding env variables, before starting the java process:
os.environ["MALLOC_CONF"]="prof:true,lg_prof_interval:26,lg_prof_sample:17"
os.environ["LD_PRELOAD"]="/usr/local/lib/libjemalloc.so"
So in the above variable prof_interval:26 states that we want a dump of the malloc allocations every 2^26 bytes, i.e 67MB. Please see the malloc parameters doc link above for the various parameters.
Setting in this file which starts off the java process ensures that these env variables are set for lifespan of the JVM.
Now start the Java service
Based on the path where the above command was executed(ex: /home/your_dir) the dumps should come in the format jeprof.218449.4.i4.heap  (in /home/your_dir/jeprof.<pid>.<nth 67MB allocation>.i<nth 67MB allocation>.heap).
Now to convert this to pdf format: jeprof --show_bytes --pdf  /usr/lib/jvm/jre-1.8.0/bin/java jeprof.218449.4.i4.heap > mypdf.pdf