Add more feature flags for tuning dynamic persistence throttling

Adds the following feature flags:
 * `persistence-throttling-window-size` for setting min/max window size
   to the same value, effectively creating a static throttle policy.
 * `persistence-throttling-ws-resize-rate` for controlling the rate
   at which the dynamic throttle policy resizes its window.

3 files changed, 33 insertions, 1 deletions

diff --git a/config-model/src/main/java/com/yahoo/config/model/deploy/TestProperties.java b/config-model/src/main/java/com/yahoo/config/model/deploy/TestProperties.java
index 9ae1a75b858..41fdea27ee6 100644
--- a/config-model/src/main/java/com/yahoo/config/model/deploy/TestProperties.java
+++ b/config-model/src/main/java/com/yahoo/config/model/deploy/TestProperties.java
@@ -72,6 +72,8 @@ public class TestProperties implements ModelContext.Properties, ModelContext.Fea
     private String mergeThrottlingPolicy = "STATIC";
     private double persistenceThrottlingWsDecrementFactor = 1.2;
     private double persistenceThrottlingWsBackoff = 0.95;
+    private int persistenceThrottlingWindowSize = -1;
+    private double persistenceThrottlingWsResizeRate = 3.0;
     private boolean inhibitDefaultMergesWhenGlobalMergesPending = false;
     private boolean useV8GeoPositions = false;
     private List<String> environmentVariables = List.of();
@@ -128,6 +130,8 @@ public class TestProperties implements ModelContext.Properties, ModelContext.Fea
     @Override public String mergeThrottlingPolicy() { return mergeThrottlingPolicy; }
     @Override public double persistenceThrottlingWsDecrementFactor() { return persistenceThrottlingWsDecrementFactor; }
     @Override public double persistenceThrottlingWsBackoff() { return persistenceThrottlingWsBackoff; }
+    @Override public int persistenceThrottlingWindowSize() { return persistenceThrottlingWindowSize; }
+    @Override public double persistenceThrottlingWsResizeRate() { return persistenceThrottlingWsResizeRate; }
     @Override public boolean inhibitDefaultMergesWhenGlobalMergesPending() { return inhibitDefaultMergesWhenGlobalMergesPending; }
     @Override public boolean useV8GeoPositions() { return useV8GeoPositions; }
     @Override public List<String> environmentVariables() { return environmentVariables; }
@@ -334,6 +338,16 @@ public class TestProperties implements ModelContext.Properties, ModelContext.Fea
         return this;
     }
 
+    public TestProperties setPersistenceThrottlingWindowSize(int windowSize) {
+        this.persistenceThrottlingWindowSize = windowSize;
+        return this;
+    }
+
+    public TestProperties setPersistenceThrottlingWsResizeRate(double resizeRate) {
+        this.persistenceThrottlingWsResizeRate = resizeRate;
+        return this;
+    }
+
     public TestProperties inhibitDefaultMergesWhenGlobalMergesPending(boolean value) {
         this.inhibitDefaultMergesWhenGlobalMergesPending = value;
         return this;
diff --git a/config-model/src/main/java/com/yahoo/vespa/model/content/storagecluster/FileStorProducer.java b/config-model/src/main/java/com/yahoo/vespa/model/content/storagecluster/FileStorProducer.java
index f3263658717..81a43108157 100644
--- a/config-model/src/main/java/com/yahoo/vespa/model/content/storagecluster/FileStorProducer.java
+++ b/config-model/src/main/java/com/yahoo/vespa/model/content/storagecluster/FileStorProducer.java
@@ -49,6 +49,8 @@ public class FileStorProducer implements StorFilestorConfig.Producer {
     private final StorFilestorConfig.Async_operation_throttler.Type.Enum asyncOperationThrottlerType;
     private final double persistenceThrottlingWsDecrementFactor;
     private final double persistenceThrottlingWsBackoff;
+    private final int persistenceThrottingWindowSize;
+    private final double persistenceThrottlingWsResizeRate;
     private final boolean useAsyncMessageHandlingOnSchedule;
 
     private static StorFilestorConfig.Response_sequencer_type.Enum convertResponseSequencerType(String sequencerType) {
@@ -75,6 +77,8 @@ public class FileStorProducer implements StorFilestorConfig.Producer {
         this.asyncOperationThrottlerType = toAsyncOperationThrottlerType(featureFlags.persistenceAsyncThrottling());
         this.persistenceThrottlingWsDecrementFactor = featureFlags.persistenceThrottlingWsDecrementFactor();
         this.persistenceThrottlingWsBackoff = featureFlags.persistenceThrottlingWsBackoff();
+        this.persistenceThrottingWindowSize = featureFlags.persistenceThrottlingWindowSize();
+        this.persistenceThrottlingWsResizeRate = featureFlags.persistenceThrottlingWsResizeRate();
         this.useAsyncMessageHandlingOnSchedule = featureFlags.useAsyncMessageHandlingOnSchedule();
     }
 
@@ -96,6 +100,11 @@ public class FileStorProducer implements StorFilestorConfig.Producer {
         throttleBuilder.type(asyncOperationThrottlerType);
         throttleBuilder.window_size_decrement_factor(persistenceThrottlingWsDecrementFactor);
         throttleBuilder.window_size_backoff(persistenceThrottlingWsBackoff);
+        if (persistenceThrottingWindowSize > 0) {
+            throttleBuilder.min_window_size(persistenceThrottingWindowSize);
+            throttleBuilder.max_window_size(persistenceThrottingWindowSize);
+        }
+        throttleBuilder.resize_rate(persistenceThrottlingWsResizeRate);
         builder.async_operation_throttler(throttleBuilder);
     }
 
diff --git a/config-model/src/test/java/com/yahoo/vespa/model/content/StorageClusterTest.java b/config-model/src/test/java/com/yahoo/vespa/model/content/StorageClusterTest.java
index 509055df7f4..fd4a21a0dd0 100644
--- a/config-model/src/test/java/com/yahoo/vespa/model/content/StorageClusterTest.java
+++ b/config-model/src/test/java/com/yahoo/vespa/model/content/StorageClusterTest.java
@@ -334,15 +334,24 @@ public class StorageClusterTest {
         var config = filestorConfigFromProducer(simpleCluster(new TestProperties()));
         assertEquals(1.2, config.async_operation_throttler().window_size_decrement_factor(), 0.0001);
         assertEquals(0.95, config.async_operation_throttler().window_size_backoff(), 0.0001);
+        assertEquals(20, config.async_operation_throttler().min_window_size());
+        assertEquals(-1, config.async_operation_throttler().max_window_size()); // <=0 implies +inf
+        assertEquals(3.0, config.async_operation_throttler().resize_rate(), 0.0001);
     }
 
     @Test
     public void persistence_dynamic_throttling_parameters_can_be_set_through_feature_flags() {
         var config = filestorConfigFromProducer(simpleCluster(new TestProperties()
                 .setPersistenceThrottlingWsDecrementFactor(1.5)
-                .setPersistenceThrottlingWsBackoff(0.8)));
+                .setPersistenceThrottlingWsBackoff(0.8)
+                .setPersistenceThrottlingWindowSize(42)
+                .setPersistenceThrottlingWsResizeRate(2.5)));
         assertEquals(1.5, config.async_operation_throttler().window_size_decrement_factor(), 0.0001);
         assertEquals(0.8, config.async_operation_throttler().window_size_backoff(), 0.0001);
+        // If window size is set, min and max are locked to the same value
+        assertEquals(42, config.async_operation_throttler().min_window_size());
+        assertEquals(42, config.async_operation_throttler().max_window_size());
+        assertEquals(2.5, config.async_operation_throttler().resize_rate(), 0.0001);
     }
 
     @Test