org.infinispan.commons.util.ProcessorInfo Maven / Gradle / Ivy
package org.infinispan.commons.util;
/**
* Provides general information about the processors on this host.
*
* @author Tristan Tarrant
*/
public class ProcessorInfo {
private ProcessorInfo() {
}
/**
* Returns the number of processors available to this process. On most operating systems this method
* simply delegates to {@link Runtime#availableProcessors()}. However, before Java 10, under Linux this strategy
* is insufficient, since the JVM does not take into consideration the process' CPU set affinity and the CGroups
* quota/period assignment. Therefore this method will analyze the Linux proc filesystem
* to make the determination. Since the CPU affinity of a process can be change at any time, this method does
* not cache the result. Calls should be limited accordingly.
*
* The number of available processors can be overridden via the system property infinispan.activeprocessorcount,
* e.g. java -Dinfinispan.activeprocessorcount=4 .... Note that this value cannot exceed the actual number
* of available processors.
*
* Since Java 10, this can also be achieved via the VM flag -XX:ActiveProcessorCount=xx.
*
* Note that on Linux, both SMT units (Hyper-Threading) and CPU cores are counted as a processor.
*
* @return the available processors on this system.
*/
public static int availableProcessors() {
return org.infinispan.commons.jdkspecific.ProcessorInfo.availableProcessors();
}
public static void main(String args[]) {
System.out.println(availableProcessors());
}
}