java process eats only 1 cpu core

Question

i run my program using maven with the following command:

mvn exec:java -Dexec.mainClass="some.path.to.my.class"

on a Linux multi-cpu server. when i check the CPU usage, i see that java eats only 1 CPU core. i read somewhere that setting the -server parameter could help.

what parameters do i have to set and how can i pass them using the mvn exec:java command?

Answer 1

You would set it in the commandlineArgs section of the configuration in your pom, as described in the documentation

eg:

 <build>
<plugins>
  <plugin>
    <groupId>org.codehaus.mojo</groupId>
    <artifactId>exec-maven-plugin</artifactId>
    <version>1.2.1</version>
    <executions>
      <execution>
        <goals>
          <goal>exec</goal>
        </goals>
      </execution>
    </executions>
    <configuration>
      <executable>maven</executable>
      <commandlineArgs>-server</commandlineArgs>
    </configuration>
  </plugin>
</plugins>

Although I'm not at all sure this is your problem - have you definitely written multithreaded code? You don't need to run the JVM in server mode to use multiple threads.

Answer 2

Processor affinity allows you to bind threads or processes to specific CPU cores.  Java doesn’t have native support for processor affinity but we can set a process affinity using the taskset command. Say we have a Java process running and we want to pin it to a specific CPU. please see following links for more details and find how do this: cpu pinning java