In FilesystemValueChecker, use 200 threads and don't waste threads on skipped keys. This yields some noticeable improvements for the wall times of null builds with even a small set of files to be checked for changes.

--
MOS_MIGRATED_REVID=104717653

1 files changed, 10 insertions, 21 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/SkyValueDirtinessChecker.java b/src/main/java/com/google/devtools/build/lib/skyframe/SkyValueDirtinessChecker.java
index 9a24122d3a..8fa15e1282 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/SkyValueDirtinessChecker.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/SkyValueDirtinessChecker.java
@@ -13,7 +13,6 @@
 // limitations under the License.
 package com.google.devtools.build.lib.skyframe;
 
-import com.google.common.base.Optional;
 import com.google.common.base.Preconditions;
 import com.google.devtools.build.lib.util.io.TimestampGranularityMonitor;
 import com.google.devtools.build.skyframe.SkyKey;
@@ -27,36 +26,26 @@ import javax.annotation.Nullable;
  */
 public abstract class SkyValueDirtinessChecker {
 
+  /** Returns {@code true} iff the checker can handle {@code key}. */
+  public abstract boolean applies(SkyKey key);
+
   /**
-   * Returns
-   * <ul>
-   *   <li>{@code null}, if the checker can't handle {@code key}.
-   *   <li>{@code Optional.<SkyValue>absent()} if the checker can handle {@code key} but was unable
-   *       to create a new value.
-   *   <li>{@code Optional.<SkyValue>of(v)} if the checker can handle {@code key} and the new value
-   *       should be {@code v}.
-   * </ul>
+   * If {@code applies(key)}, returns the new value for {@code key} or {@code null} if the checker
+   * was unable to create a new value.
    */
   @Nullable
-  public abstract Optional<SkyValue> maybeCreateNewValue(SkyKey key,
-      TimestampGranularityMonitor tsgm);
+  public abstract SkyValue createNewValue(SkyKey key, TimestampGranularityMonitor tsgm);
 
   /**
-   * Returns the result of checking whether this key's value is up to date, or null if this
-   * dirtiness checker does not apply to this key. If non-null, this answer is assumed to be
-   * definitive.
+   * If {@code applies(key)}, returns the result of checking whether this key's value is up to date.
    */
   @Nullable
-  public DirtyResult maybeCheck(SkyKey key, @Nullable SkyValue oldValue,
+  public DirtyResult check(SkyKey key, @Nullable SkyValue oldValue,
       TimestampGranularityMonitor tsgm) {
-    Optional<SkyValue> newValueMaybe = maybeCreateNewValue(key, tsgm);
-    if (newValueMaybe == null) {
-      return null;
-    }
-    if (!newValueMaybe.isPresent()) {
+    SkyValue newValue = createNewValue(key, tsgm);
+    if (newValue == null) {
       return DirtyResult.dirty(oldValue);
     }
-    SkyValue newValue = Preconditions.checkNotNull(newValueMaybe.get(), key);
     return newValue.equals(oldValue)
         ? DirtyResult.notDirty(oldValue)
         : DirtyResult.dirtyWithNewValue(oldValue, newValue);