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[GR-71288] Conditionally reduce JFR global buffer defaults to lower footprint #12502

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Merged
merged 1 commit into from
Nov 11, 2025
Merged

[GR-71288] Conditionally reduce JFR global buffer defaults to lower footprint #12502

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16 changes: 16 additions & 0 deletions substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/jfr/JfrOptionSet.java
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Original file line number Diff line number Diff line change
Expand Up @@ -75,12 +75,28 @@ public JfrOptionSet() {
}

public void validateAndAdjustMemoryOptions() {
maybeAdjustDefaults();
ensureValidMinimumSizes();
ensureValidMemoryRelations();
adjustMemoryOptions();
assert checkPostCondition();
}

/**
* We expect that Native Image executables will require lesser defaults than JFR on the JVM. So
* to reduce JFR native memory consumption, we use lower default values. We should not adjust
* default values too early (at build time) because if any settings are user defined, we
* shouldn't change any values.
*/
private void maybeAdjustDefaults() {
if (!globalBufferSize.isUserValue() && !globalBufferCount.isUserValue() && !memorySize.isUserValue()) {
globalBufferSize.setValue(globalBufferSize.defaultValue / 2);
globalBufferCount.setValue(globalBufferCount.defaultValue / 2);
// Update record of total size
memorySize.setValue(globalBufferSize.getValue() * globalBufferCount.getValue());
}
}

private void ensureValidMinimumSizes() {
if (memorySize.isUserValue() && memorySize.getValue() < MIN_MEMORY_SIZE) {
throw new IllegalStateException("The value specified for the JFR option 'memorysize' is too low. Please use at least " + MIN_MEMORY_SIZE + " bytes.");
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