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[GR-32616] [GR-33893] Adaptive GC policy improvements and option for …
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…retaining aligned chunks.

PullRequest: graal/9758
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@peter-hofer
peter-hofer committed Oct 6, 2021
2 parents a4de93f + 7af0e63 commit a7210c0
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Showing 13 changed files with 245 additions and 145 deletions.
52 changes: 28 additions & 24 deletions ...le.svm.core.genscavenge/src/com/oracle/svm/core/genscavenge/AbstractCollectionPolicy.java
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Original file line number Diff line number Diff line change
Expand Up @@ -27,6 +27,8 @@
import java.util.concurrent.locks.ReentrantLock;

import org.graalvm.compiler.api.replacements.Fold;
import org.graalvm.nativeimage.Platform;
import org.graalvm.nativeimage.Platforms;
import org.graalvm.word.UnsignedWord;
import org.graalvm.word.WordFactory;

Expand All @@ -42,8 +44,10 @@

abstract class AbstractCollectionPolicy implements CollectionPolicy {

protected static final int MIN_SPACE_SIZE_IN_ALIGNED_CHUNKS = 8;
protected static final int MAX_TENURING_THRESHOLD = 15;

@Platforms(Platform.HOSTED_ONLY.class)
static int getMaxSurvivorSpaces(Integer userValue) {
assert userValue == null || userValue >= 0;
return (userValue != null) ? userValue : AbstractCollectionPolicy.MAX_TENURING_THRESHOLD;
Expand All @@ -66,7 +70,6 @@ static int getMaxSurvivorSpaces(Integer userValue) {
protected static final int NEW_RATIO = 2; // HotSpot: -XX:NewRatio
protected static final int LARGE_MEMORY_MAX_HEAP_PERCENT = 25; // -XX:MaxRAMPercentage
protected static final int SMALL_MEMORY_MAX_HEAP_PERCENT = 50; // -XX:MinRAMPercentage
protected static final double INITIAL_HEAP_MEMORY_PERCENT = 1.5625; // -XX:InitialRAMPercentage

protected final AdaptiveWeightedAverage avgYoungGenAlignedChunkFraction = new AdaptiveWeightedAverage(DEFAULT_TIME_WEIGHT);

Expand All @@ -93,23 +96,28 @@ public boolean shouldCollectOnAllocation() {
}

@Fold
static UnsignedWord minSpaceSize() {
static UnsignedWord getAlignment() {
return HeapParameters.getAlignedHeapChunkSize();
}

@Uninterruptible(reason = "Used in uninterruptible code.", mayBeInlined = true)
static UnsignedWord alignUp(UnsignedWord size) {
return UnsignedUtils.roundUp(size, minSpaceSize());
return UnsignedUtils.roundUp(size, getAlignment());
}

@Uninterruptible(reason = "Used in uninterruptible code.", mayBeInlined = true)
static UnsignedWord alignDown(UnsignedWord size) {
return UnsignedUtils.roundDown(size, minSpaceSize());
return UnsignedUtils.roundDown(size, getAlignment());
}

@Uninterruptible(reason = "Used in uninterruptible code.", mayBeInlined = true)
static boolean isAligned(UnsignedWord size) {
return UnsignedUtils.isAMultiple(size, minSpaceSize());
return UnsignedUtils.isAMultiple(size, getAlignment());
}

@Fold
static UnsignedWord minSpaceSize() {
return getAlignment().multiply(MIN_SPACE_SIZE_IN_ALIGNED_CHUNKS);
}

@Uninterruptible(reason = "Used in uninterruptible code.", mayBeInlined = true)
Expand Down Expand Up @@ -240,10 +248,11 @@ public UnsignedWord getMinimumHeapSize() {

protected SizeParameters computeSizeParameters() {
UnsignedWord addressSpaceSize = ReferenceAccess.singleton().getAddressSpaceSize();
UnsignedWord minAllSpaces = minSpaceSize().multiply(2); // eden, old
UnsignedWord minYoungSpaces = minSpaceSize(); // eden
if (HeapParameters.getMaxSurvivorSpaces() > 0) {
minAllSpaces = minAllSpaces.add(minSpaceSize().multiply(2)); // survivor from and to
minYoungSpaces = minYoungSpaces.add(minSpaceSize().multiply(2)); // survivor from and to
}
UnsignedWord minAllSpaces = minYoungSpaces.add(minSpaceSize()); // old

UnsignedWord maxHeap;
long optionMax = SubstrateGCOptions.MaxHeapSize.getValue();
Expand All @@ -267,6 +276,7 @@ protected SizeParameters computeSizeParameters() {
maxHeap = reasonableMax;
}
}
UnsignedWord unadjustedMaxHeap = maxHeap;
maxHeap = UnsignedUtils.clamp(alignDown(maxHeap), minAllSpaces, alignDown(addressSpaceSize));

UnsignedWord maxYoung;
Expand All @@ -278,16 +288,12 @@ protected SizeParameters computeSizeParameters() {
} else {
maxYoung = maxHeap.unsignedDivide(AbstractCollectionPolicy.NEW_RATIO + 1);
}
maxYoung = UnsignedUtils.clamp(alignUp(maxYoung), minSpaceSize(), maxHeap);
maxYoung = UnsignedUtils.clamp(alignDown(maxYoung), minYoungSpaces, maxHeap.subtract(minSpaceSize()));

UnsignedWord maxOld = maxHeap.subtract(maxYoung);
maxOld = minSpaceSize(alignUp(maxOld));
UnsignedWord maxOld = alignDown(maxHeap.subtract(maxYoung));
maxHeap = maxYoung.add(maxOld);
if (maxHeap.aboveThan(addressSpaceSize)) {
maxYoung = alignDown(maxYoung.subtract(minSpaceSize()));
maxHeap = maxYoung.add(maxOld);
VMError.guarantee(maxHeap.belowOrEqual(addressSpaceSize) && maxYoung.aboveOrEqual(minSpaceSize()));
}
VMError.guarantee(maxOld.aboveOrEqual(minSpaceSize()) && maxHeap.belowOrEqual(addressSpaceSize) &&
(maxHeap.belowOrEqual(unadjustedMaxHeap) || unadjustedMaxHeap.belowThan(minAllSpaces)));

UnsignedWord minHeap = WordFactory.zero();
long optionMin = SubstrateGCOptions.MinHeapSize.getValue();
Expand All @@ -296,19 +302,15 @@ protected SizeParameters computeSizeParameters() {
}
minHeap = UnsignedUtils.clamp(alignUp(minHeap), minAllSpaces, maxHeap);

UnsignedWord initialHeap;
if (PhysicalMemory.isInitialized()) {
initialHeap = UnsignedUtils.fromDouble(UnsignedUtils.toDouble(PhysicalMemory.getCachedSize()) / 100 * AbstractCollectionPolicy.INITIAL_HEAP_MEMORY_PERCENT);
} else {
initialHeap = AbstractCollectionPolicy.SMALL_HEAP_SIZE;
}
UnsignedWord initialHeap = AbstractCollectionPolicy.SMALL_HEAP_SIZE;
initialHeap = UnsignedUtils.clamp(alignUp(initialHeap), minHeap, maxHeap);

UnsignedWord initialYoung;
if (initialHeap.equal(maxHeap)) {
initialYoung = maxYoung;
} else {
initialYoung = UnsignedUtils.clamp(alignUp(initialHeap.unsignedDivide(AbstractCollectionPolicy.NEW_RATIO + 1)), minSpaceSize(), maxYoung);
initialYoung = initialHeap.unsignedDivide(AbstractCollectionPolicy.NEW_RATIO + 1);
initialYoung = UnsignedUtils.clamp(alignUp(initialYoung), minYoungSpaces, maxYoung);
}
UnsignedWord initialSurvivor = WordFactory.zero();
if (HeapParameters.getMaxSurvivorSpaces() > 0) {
Expand All @@ -320,9 +322,11 @@ protected SizeParameters computeSizeParameters() {
* generation, which we can exceed the (current) old gen size while copying during
* collections.
*/
initialSurvivor = minSpaceSize(alignUp(initialYoung.unsignedDivide(AbstractCollectionPolicy.INITIAL_SURVIVOR_RATIO)));
initialSurvivor = initialYoung.unsignedDivide(AbstractCollectionPolicy.INITIAL_SURVIVOR_RATIO);
initialSurvivor = minSpaceSize(alignDown(initialSurvivor));
}
UnsignedWord initialEden = minSpaceSize(alignUp(initialYoung.subtract(initialSurvivor.multiply(2))));
UnsignedWord initialEden = initialYoung.subtract(initialSurvivor.multiply(2));
initialEden = minSpaceSize(alignDown(initialEden));

return new SizeParameters(maxHeap, maxYoung, initialHeap, initialEden, initialSurvivor, minHeap);
}
Expand Down
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