Optimize GC usage of iterating over all elements of GroupedLists when we don't care about the group structure, and simplify the logic for prefetching old deps.
PiperOrigin-RevId: 187681887
diff --git a/src/main/java/com/google/devtools/build/lib/util/GroupedList.java b/src/main/java/com/google/devtools/build/lib/util/GroupedList.java
index 11bef3f..3bf690a 100644
--- a/src/main/java/com/google/devtools/build/lib/util/GroupedList.java
+++ b/src/main/java/com/google/devtools/build/lib/util/GroupedList.java
@@ -20,6 +20,7 @@
import com.google.common.collect.Iterables;
import com.google.common.collect.Lists;
import com.google.devtools.build.lib.collect.compacthashset.CompactHashSet;
+import com.google.devtools.build.lib.concurrent.ThreadSafety.ThreadHostile;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
@@ -196,7 +197,7 @@
@SuppressWarnings("unchecked")
public Set<T> toSet() {
- ImmutableSet.Builder<T> builder = ImmutableSet.builder();
+ ImmutableSet.Builder<T> builder = ImmutableSet.builderWithExpectedSize(numElements());
for (Object obj : elements) {
if (obj instanceof List) {
builder.addAll((List<T>) obj);
@@ -262,6 +263,43 @@
return first.equals(second) || CompactHashSet.create(first).containsAll(second);
}
+ /** An iterator that loops through every element in each group. */
+ private class UngroupedIterator implements Iterator<T> {
+ private final Iterator<Object> iter = elements.iterator();
+ int counter = 0;
+ List<T> currentGroup;
+ int listCounter = 0;
+
+ @Override
+ public boolean hasNext() {
+ return counter < size;
+ }
+
+ @SuppressWarnings("unchecked") // Cast of Object to List<T> or T.
+ @Override
+ public T next() {
+ counter++;
+ if (currentGroup != null && listCounter < currentGroup.size()) {
+ return currentGroup.get(listCounter++);
+ }
+ Object nextGroup = iter.next();
+ if (nextGroup instanceof List) {
+ currentGroup = (List<T>) nextGroup;
+ listCounter = 1;
+ // GroupedLists shouldn't have empty lists stored.
+ return currentGroup.get(0);
+ } else {
+ currentGroup = null;
+ return (T) nextGroup;
+ }
+ }
+ }
+
+ @ThreadHostile
+ public Iterable<T> getAllElementsAsIterable() {
+ return UngroupedIterator::new;
+ }
+
@Override
public boolean equals(Object other) {
if (other == null) {
@@ -326,11 +364,6 @@
}
return ImmutableList.of((T) obj);
}
-
- @Override
- public void remove() {
- throw new UnsupportedOperationException();
- }
}
@Override
diff --git a/src/main/java/com/google/devtools/build/skyframe/InMemoryNodeEntry.java b/src/main/java/com/google/devtools/build/skyframe/InMemoryNodeEntry.java
index 76e8100..24dfeab 100644
--- a/src/main/java/com/google/devtools/build/skyframe/InMemoryNodeEntry.java
+++ b/src/main/java/com/google/devtools/build/skyframe/InMemoryNodeEntry.java
@@ -18,7 +18,6 @@
import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSet;
-import com.google.common.collect.Iterables;
import com.google.devtools.build.lib.util.GroupedList;
import com.google.devtools.build.lib.util.GroupedList.GroupedListHelper;
import com.google.devtools.build.skyframe.KeyToConsolidate.Op;
@@ -220,7 +219,7 @@
@Override
public synchronized Iterable<SkyKey> getDirectDeps() {
- return getGroupedDirectDeps().toSet();
+ return getGroupedDirectDeps().getAllElementsAsIterable();
}
/**
@@ -520,7 +519,7 @@
throws InterruptedException {
Preconditions.checkState(!isDone(), this);
if (!isDirty()) {
- return Iterables.concat(getTemporaryDirectDeps());
+ return getTemporaryDirectDeps().getAllElementsAsIterable();
} else {
// There may be duplicates here. Make sure everything is unique.
ImmutableSet.Builder<SkyKey> result = ImmutableSet.builder();
diff --git a/src/main/java/com/google/devtools/build/skyframe/QueryableGraph.java b/src/main/java/com/google/devtools/build/skyframe/QueryableGraph.java
index 26422dd..8c5af09 100644
--- a/src/main/java/com/google/devtools/build/skyframe/QueryableGraph.java
+++ b/src/main/java/com/google/devtools/build/skyframe/QueryableGraph.java
@@ -50,6 +50,15 @@
throws InterruptedException;
/**
+ * A prefetch call may be used to hint to the graph that we may call {@link #getBatch} on the
+ * specified keys later.
+ */
+ default void prefetchBatch(
+ @Nullable SkyKey requestor, Reason reason, Iterable<? extends SkyKey> keys) {
+ // Do nothing.
+ }
+
+ /**
* Examines all the given keys. Returns an iterable of keys whose corresponding nodes are
* currently available to be fetched.
*
diff --git a/src/main/java/com/google/devtools/build/skyframe/SkyFunctionEnvironment.java b/src/main/java/com/google/devtools/build/skyframe/SkyFunctionEnvironment.java
index 9646b07..d8c8f7a 100644
--- a/src/main/java/com/google/devtools/build/skyframe/SkyFunctionEnvironment.java
+++ b/src/main/java/com/google/devtools/build/skyframe/SkyFunctionEnvironment.java
@@ -20,8 +20,6 @@
import com.google.common.base.Preconditions;
import com.google.common.base.Predicates;
import com.google.common.collect.ImmutableList;
-import com.google.common.collect.ImmutableMap;
-import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Iterables;
import com.google.common.collect.Maps;
import com.google.common.collect.Sets;
@@ -151,20 +149,26 @@
boolean assertDone,
SkyKey keyForDebugging)
throws InterruptedException {
- Iterable<SkyKey> depKeysAsIterable = Iterables.concat(depKeys);
- Iterable<SkyKey> keysToPrefetch = depKeysAsIterable;
+ Set<SkyKey> depKeysAsSet = null;
if (PREFETCH_OLD_DEPS) {
- ImmutableSet.Builder<SkyKey> keysToPrefetchBuilder = ImmutableSet.builder();
- keysToPrefetchBuilder.addAll(depKeysAsIterable).addAll(oldDeps);
- keysToPrefetch = keysToPrefetchBuilder.build();
+ if (!oldDeps.isEmpty()) {
+ // Create a set here so that filtering the old deps below is fast. Once we create this set,
+ // we may as well use it for the call to evaluatorContext#getBatchValues since we've
+ // precomputed the size.
+ depKeysAsSet = depKeys.toSet();
+ evaluatorContext
+ .getGraph()
+ .prefetchBatch(
+ requestor,
+ Reason.PREFETCH,
+ Iterables.filter(oldDeps, Predicates.not(Predicates.in(depKeysAsSet))));
+ }
}
Map<SkyKey, ? extends NodeEntry> batchMap =
- evaluatorContext.getBatchValues(requestor, Reason.PREFETCH, keysToPrefetch);
- if (PREFETCH_OLD_DEPS) {
- batchMap =
- ImmutableMap.<SkyKey, NodeEntry>copyOf(
- Maps.filterKeys(batchMap, Predicates.in(ImmutableSet.copyOf(depKeysAsIterable))));
- }
+ evaluatorContext.getBatchValues(
+ requestor,
+ Reason.PREFETCH,
+ depKeysAsSet == null ? depKeys.getAllElementsAsIterable() : depKeysAsSet);
if (batchMap.size() != depKeys.numElements()) {
throw new IllegalStateException(
"Missing keys for "
@@ -316,7 +320,7 @@
keySize - directDeps.size() - (bubbleErrorInfo == null ? 0 : bubbleErrorInfo.size()),
0);
ArrayList<SkyKey> missingKeys = new ArrayList<>(expectedMissingKeySize);
- for (SkyKey key : Iterables.concat(depKeys)) {
+ for (SkyKey key : depKeys.getAllElementsAsIterable()) {
SkyValue value = maybeGetValueFromErrorOrDeps(key);
if (value == null) {
missingKeys.add(key);
