## Changelog since v1.9.0-beta.1

### Other notable changes

* Add pvc as part of equivalence hash ([#56577](https://github.com/kubernetes/kubernetes/pull/56577), [@resouer](https://github.com/resouer))

* Mark multi-scheduler graduation to beta and then v1. ([#38871](https://github.com/kubernetes/kubernetes/pull/38871), [@k82cn](https://github.com/k82cn))
* Scheduler treats StatefulSet pods as belonging to a single equivalence class. ([#39718](https://github.com/kubernetes/kubernetes/pull/39718), [@foxish](https://github.com/foxish))

 *
 * <p>See the Guava User Guide article on <a href=
 * "https://github.com/google/guava/wiki/CommonObjectUtilitiesExplained#comparecompareto">{@code
 * ComparisonChain}</a>.
 *
 * <h4 id="java8">Java 8+ equivalents</h4>
 *
 * If you are using Java version 8 or greater, you should generally use the static methods in {@link
 * Comparator} instead of {@code ComparisonChain}. The example above can be implemented like this:
 *

   * implicit).
   */
  protected Ordering() {}

  // Instance-based factories (and any static equivalents)

  /**
   * Returns the reverse of this ordering; the {@code Ordering} equivalent to {@link
   * Collections#reverseOrder(Comparator)}.
   *
   * <p><b>Java 8+ users:</b> Use {@code thisComparator.reversed()} instead.
   */

### SIG Scheduling

- The equivalence class cache has been redesigned to be a two level cache, resulting in a significant increase in scheduling throughput and performance. ([#65714](https://github.com/kubernetes/kubernetes/pull/65714), [@resouer](https://github.com/resouer))

* Use monotonically increasing generation to prevent scheduler equivalence cache race. ([#67308](https://github.com/kubernetes/kubernetes/pull/67308), [@cofyc](https://github.com/cofyc))

  /**
   * Determines if the given iterable contains no elements.
   *
   * <p>There is no precise {@link Iterator} equivalent to this method, since one can only ask an
   * iterator whether it has any elements <i>remaining</i> (which one does using {@link
   * Iterator#hasNext}).
   *
   * <p><b>{@code Stream} equivalent:</b> {@code !stream.findAny().isPresent()}
   *
   * @return {@code true} if the iterable contains no elements

   *
   * <p><b>Comparison to {@code java.util.Optional}:</b> this method is equivalent to Java 8's
   * {@code Optional.ofNullable}.
   */
  public static <T> Optional<T> fromNullable(@Nullable T nullableReference) {
    return (nullableReference == null) ? Optional.<T>absent() : new Present<T>(nullableReference);
  }

  /**
   * Returns the equivalent {@code com.google.common.base.Optional} value to the given {@code

  }

  protected void initMapWithNullKey() {
    resetMap(createArrayWithNullKey());
  }

  protected void initMapWithNullValue() {
    resetMap(createArrayWithNullValue());
  }

  /**
   * Equivalent to {@link #expectMissingKeys(Object[]) expectMissingKeys} {@code (null)} except that
   * the call to {@code contains(null)} is permitted to throw a {@code NullPointerException}.
   *

    return array;
  }

  protected void initCollectionWithNullElement() {
    E[] array = createArrayWithNullElement();
    resetContainer(getSubjectGenerator().create(array));
  }

  /**
   * Equivalent to {@link #expectMissing(Object[]) expectMissing}{@code (null)} except that the call
   * to {@code contains(null)} is permitted to throw a {@code NullPointerException}.
   *