Package com.carrotsearch.hppc

Class RamUsageEstimator

java.lang.Object
com.carrotsearch.hppc.RamUsageEstimator
public class RamUsageEstimator extends Object
Helper class that helps estimate memory usage

Mostly forked from Lucene tag releases/lucene-solr/8.5.1

  • Field Details

    • ONE_KB

      public static final long ONE_KB
      One kilobyte bytes.
      See Also:

    • ONE_MB

      public static final long ONE_MB
      One megabyte bytes.
      See Also:

    • ONE_GB

      public static final long ONE_GB
      One gigabyte bytes.
      See Also:

    • COMPRESSED_REFS_ENABLED

      public static final boolean COMPRESSED_REFS_ENABLED
      True, iff compressed references (oops) are enabled by this JVM

    • NUM_BYTES_OBJECT_REF

      public static final int NUM_BYTES_OBJECT_REF
      Number of bytes this JVM uses to represent an object reference.

    • NUM_BYTES_OBJECT_HEADER

      public static final int NUM_BYTES_OBJECT_HEADER
      Number of bytes to represent an object header (no fields, no alignments).

    • NUM_BYTES_ARRAY_HEADER

      public static final int NUM_BYTES_ARRAY_HEADER
      Number of bytes to represent an array header (no content, but with alignments).

    • NUM_BYTES_OBJECT_ALIGNMENT

      public static final int NUM_BYTES_OBJECT_ALIGNMENT
      A constant specifying the object alignment boundary inside the JVM. Objects will always take a full multiple of this constant, possibly wasting some space.

    • primitiveSizes

      public static final Map<Class<?>,Integer> primitiveSizes
      Sizes of primitive classes.

  • Method Details

    • alignObjectSize

      public static long alignObjectSize(long size)
      Aligns an object size to be the next multiple of NUM_BYTES_OBJECT_ALIGNMENT.

    • shallowUsedSizeOfArray

      public static long shallowUsedSizeOfArray(Object array, int usedSize)
      Return used part of shallow size of any array.
      Parameters:
      usedSize - Size that array is actually used

    • shallowSizeOfArray

      public static long shallowSizeOfArray(Object array)
      Return shallow size of any array.