Quarkus

In part one of this series, we took a detailed look at Red Hat JBoss Enterprise Application Platform (JBoss EAP) quickstarts helloworld quickstart as a starting point for understanding how to modernize a Java application using technologies (CDI and Servlet 3) supported in Quarkus. In this part, we'll continue our discussion of modernization with a look at memory consumption.

Measuring performances is a fundamental topic when dealing with a modernization process, and memory consumption reporting is part of performance analysis. It's worth starting with these tools from the very beginning so that they can be used to evaluate the improvements achieved during the modernization process.

A detailed introduction to measuring memory usage is available in Measuring Performance—How do we measure memory usage? Quarkus guide.

In the following paragraphs, memory consumption data for the three different application flavors presented above (JBoss EAP, packaged JAR, and native executable) will be captured in a Linux system using pmap and ps tools.

JBoss EAP

Start a JBoss EAP instance by following the "Deploy helloworld" section, and retrieve its PID (e.g., 7268) using the command:

$ pgrep -lf jboss
7268 java

Note: Add the -a option to retrieve the full command line (i.e., $ pgrep -af jboss).

Now, the 7268 PID can be used to execute the following two commands:

$ ps -o pid,rss,command -p 7268
PID RSS COMMAND 
7268 665348 java -D[Standalone] -server -verbose:gc -Xloggc:/home/mrizzi/Tools/jboss-eap-7.2.0/jboss-eap-7.2/standalone/log/gc.log -XX:+PrintGCDetails -XX:+PrintGCDateStamps -XX:+UseGCLogFileRotation -XX:NumberOfGCLogFiles=5 -XX:GCLogFileSize=3M -XX:-TraceClassUnloading -Xms1303m -Xmx1303m -XX:MetaspaceSize=96M -XX:MaxMetaspaceSize=256m -Djava.net.preferI

and:

$ pmap -x 7268
7268:   java -D[Standalone] -server -verbose:gc -Xloggc:/home/mrizzi/Tools/jboss-eap-7.2.0/jboss-eap-7.2/standalone/log/gc.log -XX:+PrintGCDetails -XX:+PrintGCDateStamps -XX:+UseGCLogFileRotation -XX:NumberOfGCLogFiles=5 -XX:GCLogFileSize=3M -XX:-TraceClassUnloading -Xms1303m -Xmx1303m -XX:MetaspaceSize=96M -XX:MaxMetaspaceSize=256m -Djava.net.preferIPv4Stack=true -Djboss.modules.system.pkgs=org.jboss.byteman -Djava.awt.headless=true -Dorg.jboss.boot.log.file=/home/mrizzi/Tools/jboss-eap-7.2.0/jboss-eap-7.2/standa
Address           Kbytes     RSS   Dirty Mode  Mapping
00000000ae800000 1348608  435704  435704 rw---   [ anon ]
0000000100d00000 1035264       0       0 -----   [ anon ]
000055e4d2c2f000       4       4       0 r---- java
000055e4d2c30000       4       4       0 r-x-- java
000055e4d2c31000       4       0       0 r---- java
000055e4d2c32000       4       4       4 r---- java
000055e4d2c33000       4       4       4 rw--- java
[...]
ffffffffff600000       4       0       0 r-x--   [ anon ]
---------------- ------- ------- -------
total kB         3263224  672772  643024

Evaluating the RSS values, it looks like JBoss EAP memory consumption is around 650MB.

Packaged JAR

Referring to the "Run the helloworld packaged JAR" section, start the packaged JAR application by executing:

$ java -jar ./target/helloworld-<version>-runner.jar

and retrieve its PID using again the pgrep command (this time with the -a option described in the note above):

$ pgrep -af helloworld
6408 java -jar ./target/helloworld-<version>-runner.jar

Following the same process, use the 6408 PID to evaluate memory consumption by executing:

$ ps -o pid,rss,command -p 6408
  PID   RSS COMMAND
 6408 125732 java -jar ./target/helloworld-quarkus-runner.jar

and:

$ pmap -x 6408
6408:   java -jar ./target/helloworld-quarkus-runner.jar
Address           Kbytes     RSS   Dirty Mode  Mapping
00000005d3200000  337408       0       0 rw---   [ anon ]
00000005e7b80000 5046272       0       0 -----   [ anon ]
000000071bb80000  168448   57576   57576 rw---   [ anon ]
0000000726000000 2523136       0       0 -----   [ anon ]
00000007c0000000    2176    2088    2088 rw---   [ anon ]
00000007c0220000 1046400       0       0 -----   [ anon ]
00005645b85d6000       4       4       0 r---- java
00005645b85d7000       4       4       0 r-x-- java
00005645b85d8000       4       0       0 r---- java
00005645b85d9000       4       4       4 r---- java
00005645b85da000       4       4       4 rw--- java
[...]
ffffffffff600000       4       0       0 r-x--   [ anon ]
---------------- ------- ------- -------
total kB         12421844  133784  115692

Evaluating the RSS values, it looks like packaged JAR memory consumption is around 130MB.

Native executable

In this case, following the "Run the helloworld native executable" section, the native executable application can be started with the command:

$ ./target/helloworld-<version>-runner

Its PID can be retrieved with the same command used in the previous case:

$ pgrep -af helloworld
6948 ./target/helloworld-<version>-runner

Then, use the 6948 PID with the ps and pmap commands:

$ ps -o pid,rss,command -p 6948
  PID   RSS COMMAND
 6948 19084 ./target/helloworld-quarkus-runner

and:

$ pmap -x 6948
6948:   ./target/helloworld-quarkus-runner
Address           Kbytes     RSS   Dirty Mode  Mapping
0000000000400000      12      12       0 r---- helloworld-quarkus-runner
0000000000403000   10736    8368       0 r-x-- helloworld-quarkus-runner
0000000000e7f000    7812    6144       0 r---- helloworld-quarkus-runner
0000000001620000    2024    1448     308 rw--- helloworld-quarkus-runner
000000000181a000       4       4       4 r---- helloworld-quarkus-runner
000000000181b000      16      16      12 rw--- helloworld-quarkus-runner
0000000001e10000    1740     156     156 rw---   [ anon ]
[...]
ffffffffff600000       4       0       0 r-x--   [ anon ]
---------------- ------- ------- -------
total kB         1456800   20592    2684

Evaluating the RSS values, it looks like native executable memory consumption is around 20MB.

Memory consumption comparison

In summary, the memory consumption data retrieved are:

  • JBoss EAP: 650MB
  • Packaged JAR: 130MB
  • Native builder: 20MB

So, it's clear that there are advantages in terms of memory usage thanks to running the native executable.

Conclusion

In these articles, we explored how to modernize a Java application using technologies (CDI and Servlet 3) supported in Quarkus and provided an overview of different ways to develop, build, and run an application. We also showed how to capture memory consumption data in order to evaluate the improvements achieved during the modernization process.  These concepts provide the fundamentals for understanding how Quarkus works and why it's so useful, no matter whether the app is a simple helloworld quickstart or a more complex and production-level application.

Last updated: July 1, 2020