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Optimize some parts of Skyframe node deletion, especially for the cas…
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…e of discarding the analysis cache on a configuration change:

1. Avoid processing to-be-deleted direct deps of a node being deleted: removing this node from the dep's reverse deps is useful only as a consistency check and is too expensive to justify, given that it's been a long time since there was a bug there.

2. To make (1) more effective, in an analysis-cache-discarding event, eagerly mark all ActionLookupData nodes as to-be-deleted: they will be deleted anyway, since they depend on ActionLookupKey nodes, and marking them eagerly means we can apply the optimization in (1).

3. Don't make an ImmutableSet copy of the reverse deps in ReverseDepsUtility#getReverseDeps when the node is about to be deleted: the consistency check is not worth the cost.

This should reduce CPU, memory churn, and contention.

PiperOrigin-RevId: 388715102
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@janakdr @copybara-github
janakdr authored and copybara-github committed Aug 4, 2021
1 parent d0d0c5f commit 3ea7559
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Showing 6 changed files with 124 additions and 64 deletions.
26 changes: 22 additions & 4 deletions src/main/java/com/google/devtools/build/lib/skyframe/SkyframeExecutor.java
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Original file line number Diff line number Diff line change
Expand Up @@ -962,6 +962,11 @@ protected boolean isAnalysisIncremental() {
return tracksStateForIncrementality();
}

@ForOverride
protected boolean shouldDeleteActionNodesWhenDroppingAnalysis() {
return true;
}

/**
* If not null, this is the only source root in the build, corresponding to the single element in
* a single-element package path. Such a single-source-root build need not plant the execroot
Expand Down Expand Up @@ -1115,8 +1120,12 @@ public abstract void clearAnalysisCache(
protected final void deleteAnalysisNodes() {
memoizingEvaluator.delete(
keepBuildConfigurationNodesWhenDiscardingAnalysis
? SkyframeExecutor::basicAnalysisInvalidatingPredicate
: SkyframeExecutor::fullAnalysisInvalidatingPredicate);
? shouldDeleteActionNodesWhenDroppingAnalysis()
? SkyframeExecutor::basicAnalysisInvalidatingPredicateWithActions
: SkyframeExecutor::basicAnalysisInvalidatingPredicate
: shouldDeleteActionNodesWhenDroppingAnalysis()
? SkyframeExecutor::fullAnalysisInvalidatingPredicateWithActions
: SkyframeExecutor::fullAnalysisInvalidatingPredicate);
}

// We delete any value that can hold an action -- all subclasses of ActionLookupKey.
Expand All @@ -1125,10 +1134,19 @@ private static boolean basicAnalysisInvalidatingPredicate(SkyKey key) {
return key instanceof ArtifactNestedSetKey || key instanceof ActionLookupKey;
}

// Also remove ActionLookupData since all such nodes depend on ActionLookupKey nodes and deleting
// en masse is cheaper than deleting via graph traversal (b/192863968).
private static boolean basicAnalysisInvalidatingPredicateWithActions(SkyKey key) {
return basicAnalysisInvalidatingPredicate(key) || key instanceof ActionLookupData;
}

// We may also want to remove BuildConfigurationValue.Keys to fix a minor memory leak there.
private static boolean fullAnalysisInvalidatingPredicate(SkyKey key) {
return key instanceof ArtifactNestedSetKey
|| key instanceof ActionLookupKey
return basicAnalysisInvalidatingPredicate(key) || key instanceof BuildConfigurationValue.Key;
}

private static boolean fullAnalysisInvalidatingPredicateWithActions(SkyKey key) {
return basicAnalysisInvalidatingPredicateWithActions(key)
|| key instanceof BuildConfigurationValue.Key;
}

Expand Down
13 changes: 7 additions & 6 deletions src/main/java/com/google/devtools/build/skyframe/InMemoryNodeEntry.java
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Original file line number Diff line number Diff line change
Expand Up @@ -23,6 +23,7 @@
import com.google.devtools.build.skyframe.KeyToConsolidate.OpToStoreBare;
import com.google.errorprone.annotations.ForOverride;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Set;
import javax.annotation.Nullable;
Expand Down Expand Up @@ -458,21 +459,21 @@ public synchronized void removeInProgressReverseDep(SkyKey reverseDep) {
}

@Override
public synchronized Set<SkyKey> getReverseDepsForDoneEntry() {
public synchronized Collection<SkyKey> getReverseDepsForDoneEntry() {
assertKeepRdeps();
Preconditions.checkState(isDone(), "Called on not done %s", this);
return ReverseDepsUtility.getReverseDeps(this);
return ReverseDepsUtility.getReverseDeps(this, /*checkConsistency=*/ true);
}

@Override
public synchronized Set<SkyKey> getAllReverseDepsForNodeBeingDeleted() {
public synchronized Collection<SkyKey> getAllReverseDepsForNodeBeingDeleted() {
assertKeepRdeps();
if (!isDone()) {
// This consolidation loses information about pending reverse deps to signal, but that is
// unimportant since this node is being deleted.
ReverseDepsUtility.consolidateDataAndReturnNewElements(this, getOpToStoreBare());
}
return ReverseDepsUtility.getReverseDeps(this);
return ReverseDepsUtility.getReverseDeps(this, /*checkConsistency=*/ false);
}

@Override
Expand Down Expand Up @@ -525,7 +526,7 @@ public synchronized MarkedDirtyResult markDirty(DirtyType dirtyType) {
this.directDeps = null;
return new MarkedDirtyResult(
KeepEdgesPolicy.ALL.equals(keepEdges())
? ReverseDepsUtility.getReverseDeps(this)
? ReverseDepsUtility.getReverseDeps(this, /*checkConsistency=*/ true)
: ImmutableList.of());
}
if (dirtyType.equals(DirtyType.FORCE_REBUILD)) {
Expand Down Expand Up @@ -723,7 +724,7 @@ protected synchronized InMemoryNodeEntry cloneNodeEntry(InMemoryNodeEntry newEnt
newEntry.value = value;
newEntry.lastChangedVersion = this.lastChangedVersion;
newEntry.lastEvaluatedVersion = this.lastEvaluatedVersion;
for (SkyKey reverseDep : ReverseDepsUtility.getReverseDeps(this)) {
for (SkyKey reverseDep : ReverseDepsUtility.getReverseDeps(this, /*checkConsistency=*/ true)) {
ReverseDepsUtility.addReverseDep(newEntry, reverseDep);
}
newEntry.directDeps = directDeps;
Expand Down
59 changes: 36 additions & 23 deletions src/main/java/com/google/devtools/build/skyframe/InvalidatingNodeVisitor.java
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Original file line number Diff line number Diff line change
Expand Up @@ -261,8 +261,6 @@ public void visit(Iterable<SkyKey> keys, InvalidationType invalidationType) {
// normal rdep. That information is used to remove this node as an rdep from the
// correct list of rdeps in the child -- because of our compact storage of rdeps,
// checking which list contains this parent could be expensive.
Set<SkyKey> signalingDeps =
entry.isDone() ? ImmutableSet.of() : entry.getTemporaryDirectDeps().toSet();
Iterable<SkyKey> directDeps;
try {
directDeps =
Expand All @@ -277,29 +275,44 @@ public void visit(Iterable<SkyKey> keys, InvalidationType invalidationType) {
+ entry,
e);
}
// No need to do reverse dep surgery on nodes that are deleted/about to be deleted
// anyway.
Map<SkyKey, ? extends NodeEntry> depMap =
graph.getBatch(key, Reason.INVALIDATION, directDeps);
for (Map.Entry<SkyKey, ? extends NodeEntry> directDepEntry : depMap.entrySet()) {
NodeEntry dep = directDepEntry.getValue();
if (dep != null) {
if (dep.isDone() || !signalingDeps.contains(directDepEntry.getKey())) {
try {
dep.removeReverseDep(key);
} catch (InterruptedException e) {
throw new IllegalStateException(
"Deletion cannot happen on a graph that may have blocking "
+ "operations: "
+ key
+ ", "
+ entry,
e);
graph.getBatch(
key,
Reason.INVALIDATION,
Iterables.filter(
directDeps,
k ->
!visited.contains(k)
&& !pendingVisitations.contains(
Pair.of(k, InvalidationType.DELETED))));
if (!depMap.isEmpty()) {
// Don't do set operation below for signalingDeps if there's no work.
Set<SkyKey> signalingDeps =
entry.isDone() ? ImmutableSet.of() : entry.getTemporaryDirectDeps().toSet();
for (Map.Entry<SkyKey, ? extends NodeEntry> directDepEntry : depMap.entrySet()) {
NodeEntry dep = directDepEntry.getValue();
if (dep != null) {
if (dep.isDone() || !signalingDeps.contains(directDepEntry.getKey())) {
try {
dep.removeReverseDep(key);
} catch (InterruptedException e) {
throw new IllegalStateException(
"Deletion cannot happen on a graph that may have blocking "
+ "operations: "
+ key
+ ", "
+ entry,
e);
}
} else {
// This step is not strictly necessary, since all in-progress nodes are
// deleted during graph cleaning, which happens in a single
// DeletingNodeVisitor visitation, aka the one right now. We leave this
// here in case the logic changes.
dep.removeInProgressReverseDep(key);
}
} else {
// This step is not strictly necessary, since all in-progress nodes are
// deleted during graph cleaning, which happens in a single
// DeletingNodeVisitor visitation, aka the one right now. We leave this
// here in case the logic changes.
dep.removeInProgressReverseDep(key);
}
}
}
Expand Down
7 changes: 6 additions & 1 deletion src/main/java/com/google/devtools/build/skyframe/ReverseDepsUtility.java
View file
Original file line number Diff line number Diff line change
Expand Up @@ -15,6 +15,7 @@

import com.google.common.base.MoreObjects;
import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableCollection;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Iterables;
Expand Down Expand Up @@ -123,7 +124,8 @@ static void removeReverseDep(InMemoryNodeEntry entry, SkyKey reverseDep) {
maybeDelayReverseDepOp(entry, reverseDep, Op.REMOVE);
}

static ImmutableSet<SkyKey> getReverseDeps(InMemoryNodeEntry entry) {
static ImmutableCollection<SkyKey> getReverseDeps(
InMemoryNodeEntry entry, boolean checkConsistency) {
consolidateData(entry);

// TODO(bazel-team): Unfortunately, we need to make a copy here right now to be on the safe side
Expand All @@ -134,6 +136,9 @@ static ImmutableSet<SkyKey> getReverseDeps(InMemoryNodeEntry entry) {
} else {
@SuppressWarnings("unchecked")
List<SkyKey> reverseDeps = (List<SkyKey>) entry.getReverseDepsRawForReverseDepsUtil();
if (!checkConsistency) {
return ImmutableList.copyOf(reverseDeps);
}
ImmutableSet<SkyKey> set = ImmutableSet.copyOf(reverseDeps);
maybeAssertReverseDepsConsistency(
set.size() == reverseDeps.size(),
Expand Down
45 changes: 24 additions & 21 deletions src/test/java/com/google/devtools/build/skyframe/EagerInvalidatorTest.java
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Original file line number Diff line number Diff line change
Expand Up @@ -463,7 +463,7 @@ public void interruptThreadInReceiver() throws Exception {
SkyKey[] values = constructLargeGraph(graphSize);
eval(/*keepGoing=*/false, values);
final Thread mainThread = Thread.currentThread();
for (int run = 0; run < tries; run++) {
for (int run = 0; run < tries + 1; run++) {
Set<Pair<SkyKey, InvalidationType>> valuesToInvalidate = getValuesToInvalidate(values);
// Find how many invalidations will actually be enqueued for invalidation in the first round,
// so that we can interrupt before all of them are done.
Expand All @@ -475,25 +475,28 @@ public void interruptThreadInReceiver() throws Exception {
}
}
int countDownStart = validValuesToDo > 0 ? random.nextInt(validValuesToDo) : 0;
final CountDownLatch countDownToInterrupt = new CountDownLatch(countDownStart);
final DirtyTrackingProgressReceiver receiver =
new DirtyTrackingProgressReceiver(
new EvaluationProgressReceiver() {
@Override
public void invalidated(SkyKey skyKey, InvalidationState state) {
countDownToInterrupt.countDown();
if (countDownToInterrupt.getCount() == 0) {
mainThread.interrupt();
// Wait for the main thread to be interrupted uninterruptibly, because the main
// thread is going to interrupt us, and we don't want to get into an interrupt
// fight. Only if we get interrupted without the main thread also being
// interrupted will this throw an InterruptedException.
TrackingAwaiter.INSTANCE.awaitLatchAndTrackExceptions(
visitor.get().getInterruptionLatchForTestingOnly(),
"Main thread was not interrupted");
}
}
});
CountDownLatch countDownToInterrupt = new CountDownLatch(countDownStart);
// Make sure final invalidation finishes.
DirtyTrackingProgressReceiver receiver =
run == tries
? new DirtyTrackingProgressReceiver(null)
: new DirtyTrackingProgressReceiver(
new EvaluationProgressReceiver() {
@Override
public void invalidated(SkyKey skyKey, InvalidationState state) {
countDownToInterrupt.countDown();
if (countDownToInterrupt.getCount() == 0) {
mainThread.interrupt();
// Wait for the main thread to be interrupted uninterruptibly, because the
// main thread is going to interrupt us, and we don't want to get into an
// interrupt fight. Only if we get interrupted without the main thread also
// being interrupted will this throw an InterruptedException.
TrackingAwaiter.INSTANCE.awaitLatchAndTrackExceptions(
visitor.get().getInterruptionLatchForTestingOnly(),
"Main thread was not interrupted");
}
}
});
try {
invalidate(
graph,
Expand All @@ -502,7 +505,7 @@ public void invalidated(SkyKey skyKey, InvalidationState state) {
.toArray(new SkyKey[0]));
assertThat(state.getInvalidationsForTesting()).isEmpty();
} catch (InterruptedException e) {
// Expected.
assertThat(run).isLessThan(tries);
}
if (state.isEmpty()) {
// Ran out of values to invalidate.
Expand Down
38 changes: 29 additions & 9 deletions src/test/java/com/google/devtools/build/skyframe/ReverseDepsUtilityTest.java
View file
Original file line number Diff line number Diff line change
Expand Up @@ -33,7 +33,7 @@ public class ReverseDepsUtilityTest {
@Parameters(name = "numElements-{0}")
public static List<Object[]> parameters() {
List<Object[]> params = new ArrayList<>();
for (int i = 0; i < 20; i++) {
for (int i = 1; i < 2; i++) {
params.add(new Object[] {i});
}
return params;
Expand All @@ -52,11 +52,13 @@ public void testAddAndRemove() {
}
// Not a big test but at least check that it does not blow up.
assertThat(ReverseDepsUtility.toString(example)).isNotEmpty();
assertThat(ReverseDepsUtility.getReverseDeps(example)).hasSize(numElements);
assertThat(ReverseDepsUtility.getReverseDeps(example, /*checkConsistency=*/ true))
.hasSize(numElements);
for (int i = 0; i < numRemovals; i++) {
ReverseDepsUtility.removeReverseDep(example, Key.create(i));
}
assertThat(ReverseDepsUtility.getReverseDeps(example)).hasSize(numElements - numRemovals);
assertThat(ReverseDepsUtility.getReverseDeps(example, /*checkConsistency=*/ true))
.hasSize(numElements - numRemovals);
assertThat(example.getReverseDepsDataToConsolidateForReverseDepsUtil()).isNull();
}
}
Expand All @@ -69,11 +71,13 @@ public void testAddAllAndRemove() {
for (int j = 0; j < numElements; j++) {
ReverseDepsUtility.addReverseDep(example, Key.create(j));
}
assertThat(ReverseDepsUtility.getReverseDeps(example)).hasSize(numElements);
assertThat(ReverseDepsUtility.getReverseDeps(example, /*checkConsistency=*/ true))
.hasSize(numElements);
for (int i = 0; i < numRemovals; i++) {
ReverseDepsUtility.removeReverseDep(example, Key.create(i));
}
assertThat(ReverseDepsUtility.getReverseDeps(example)).hasSize(numElements - numRemovals);
assertThat(ReverseDepsUtility.getReverseDeps(example, /*checkConsistency=*/ true))
.hasSize(numElements - numRemovals);
assertThat(example.getReverseDepsDataToConsolidateForReverseDepsUtil()).isNull();
}
}
Expand All @@ -88,12 +92,25 @@ public void testDuplicateCheckOnGetReverseDeps() {
ReverseDepsUtility.addReverseDep(example, Key.create(0));
if (numElements == 0) {
// Will not throw.
ReverseDepsUtility.getReverseDeps(example);
assertThat(ReverseDepsUtility.getReverseDeps(example, /*checkConsistency=*/ true)).isEmpty();
} else {
assertThrows(Exception.class, () -> ReverseDepsUtility.getReverseDeps(example));
assertThrows(
RuntimeException.class,
() -> ReverseDepsUtility.getReverseDeps(example, /*checkConsistency=*/ true));
}
}

@Test
public void duplicateAddNoThrowWithoutCheck() {
InMemoryNodeEntry example = new InMemoryNodeEntry();
for (int i = 0; i < numElements; i++) {
ReverseDepsUtility.addReverseDep(example, Key.create(i));
}
ReverseDepsUtility.addReverseDep(example, Key.create(0));
assertThat(ReverseDepsUtility.getReverseDeps(example, /*checkConsistency=*/ false))
.hasSize(numElements + 1);
}

@Test
public void doubleAddThenRemove() {
InMemoryNodeEntry example = new InMemoryNodeEntry();
Expand All @@ -102,7 +119,9 @@ public void doubleAddThenRemove() {
// Should only fail when we call getReverseDeps().
ReverseDepsUtility.addReverseDep(example, key);
ReverseDepsUtility.removeReverseDep(example, key);
assertThrows(IllegalStateException.class, () -> ReverseDepsUtility.getReverseDeps(example));
assertThrows(
IllegalStateException.class,
() -> ReverseDepsUtility.getReverseDeps(example, /*checkConsistency=*/ true));
}

@Test
Expand All @@ -129,7 +148,8 @@ public void addRemoveAdd() {
ReverseDepsUtility.addReverseDep(example, key);
ReverseDepsUtility.removeReverseDep(example, key);
ReverseDepsUtility.addReverseDep(example, key);
assertThat(ReverseDepsUtility.getReverseDeps(example)).containsExactly(fixedKey, key);
assertThat(ReverseDepsUtility.getReverseDeps(example, /*checkConsistency=*/ true))
.containsExactly(fixedKey, key);
}

private static class Key extends AbstractSkyKey<Integer> {
Expand Down

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