Vert.x 4.5.13 · io.vertx.core.impl.cpu.CpuCoreSensor

Utility class providing the number of CPU cores available. On Linux, to handle CGroups, it reads and parses the /proc/self/status file.

This class derives from https://github.com/wildfly/wildfly-common/blob/master/src/main/java/org/wildfly/common/cpu/ProcessorInfo.java licensed under the Apache Software License 2.0.

Field Summary

Modifier and Type	Field and Description
private static final byte[]	BITS
private static final String	CPUS_ALLOWED

Constructor Summary

Access	Constructor and Description
public	CpuCoreSensor()

Method Summary

Modifier and Type	Method and Description
public static int	Returns: the available processors on this system. availableProcessors() Returns the number of processors available to this process.
private static int	determineProcessors()
protected static int	readCPUMask(File file)

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

BITS	back to summary
private static final byte[] BITS

CPUS_ALLOWED	back to summary
private static final String CPUS_ALLOWED

Constructor Detail

CpuCoreSensor	back to summary
public CpuCoreSensor()

Method Detail

availableProcessors back to summary

availableProcessors	back to summary
public static int availableProcessors() Returns the number of processors available to this process. On most operating systems this method simply delegates to `Runtime#availableProcessors()`. However, on Linux, this strategy is insufficient, since the JVM does not take into consideration the process' CPU set affinity which is employed by cgroups and numactl. 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. Note that on Linux, both SMT units (Hyper-Threading) and CPU cores are counted as a processor. This method is used to configure the default number of event loops. This settings can be overridden by the user. Returns:int the available processors on this system.

public static int availableProcessors()

Returns the number of processors available to this process.

On most operating systems this method simply delegates to Runtime#availableProcessors(). However, on Linux, this strategy is insufficient, since the JVM does not take into consideration the process' CPU set affinity which is employed by cgroups and numactl. 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.

Note that on Linux, both SMT units (Hyper-Threading) and CPU cores are counted as a processor.

This method is used to configure the default number of event loops. This settings can be overridden by the user.

Returns:int: the available processors on this system.

determineProcessors	back to summary
private static int determineProcessors()

readCPUMask	back to summary
protected static int readCPUMask(File file) throws IOException