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.