javajava-11jemalloc

Jemalloc: Java Native Memory profiling shows 100% je_prof_backtrace

We have a multi-threaded production Java application. We are trying to check the native memory usage as mentioned in this post.

But on the dump I am seeing 100% memory is being taken by je_prof_backtrace

ubuntu@platform1:/tmp/jemalloc_dump$ /home/ubuntu/jemalloc/bin/jeprof --show_bytes `which java` /tmp/jemalloc_dump/tsdb.62634.6454.i6454.heap
Using local file /usr/bin/java.
Using local file /tmp/jemalloc_dump/tsdb.62634.6454.i6454.heap
Welcome to jeprof!  For help, type 'help'.
(jeprof) top
Total: 815965512 B
815965512 100.0% 100.0% 815965512 100.0% je_prof_backtrace
       0   0.0% 100.0% 268451840  32.9% 0x00007f1338bd83a5
       0   0.0% 100.0% 279057735  34.2% 0x00007f13390d615a
       0   0.0% 100.0% 268455936  32.9% 0x00007f133918adda
       0   0.0% 100.0% 268455936  32.9% AllocateHeap
       0   0.0% 100.0% 268455936  32.9% JVM_MonitorWait
       0   0.0% 100.0% 268451840  32.9% Java_java_util_zip_Inflater_inflateBytesBytes
       0   0.0% 100.0% 268455936  32.9% ObjectSynchronizer::inflate
       0   0.0% 100.0% 268455936  32.9% ObjectSynchronizer::omAlloc
       0   0.0% 100.0% 268455936  32.9% ObjectSynchronizer::wait```

Output is like below if I use text

(jeprof) text
Total: 815965512 B
815965512 100.0% 100.0% 815965512 100.0% je_prof_backtrace
       0   0.0% 100.0% 268451840  32.9% 0x00007f1338bd83a5
       0   0.0% 100.0% 279057735  34.2% 0x00007f13390d615a
       0   0.0% 100.0% 268455936  32.9% 0x00007f133918adda
       0   0.0% 100.0% 268455936  32.9% AllocateHeap
       0   0.0% 100.0% 268455936  32.9% JVM_MonitorWait
       0   0.0% 100.0% 268451840  32.9% Java_java_util_zip_Inflater_inflateBytesBytes
       0   0.0% 100.0% 268455936  32.9% ObjectSynchronizer::inflate
       0   0.0% 100.0% 268455936  32.9% ObjectSynchronizer::omAlloc
       0   0.0% 100.0% 268455936  32.9% ObjectSynchronizer::wait

Steps followed.

  1. Downloaded jemalloc 5.2.1 release tag from here.
  2. ./autogen.sh --enable-prof inside the directory where jmalloc tar in untared.
  3. make

Application was started with the below options

export JEMALLOC_PATH=/home/ubuntu/jemalloc
export MALLOC_CONF=prof:true,lg_prof_interval:21,lg_prof_sample:28,prof_prefix:/tmp/jemalloc_dump/tsdb
LD_PRELOAD=${JEMALLOC_PATH}/lib/libjemalloc.so.2 \
java ...

I am new to jemalloc. Can someone suggest what could be going wrong?

ubuntu@platform1:/tmp/jemalloc_dump$ java -version
openjdk version "11.0.11" 2021-04-20 LTS
OpenJDK Runtime Environment Zulu11.48+22-SA (build 11.0.11+9-LTS)
OpenJDK 64-Bit Server VM Zulu11.48+22-SA (build 11.0.11+9-LTS, mixed mode)
Solution

  • Try configuring using the below flags :

    ./configure --enable-prof --enable-stats --enable-debug --enable-fill