- If less than 16G memory only use single flush thread.

- No more than 1 flushtread per 8 vcpus.

1 files changed, 4 insertions, 1 deletions

diff --git a/config-model/src/main/java/com/yahoo/vespa/model/search/NodeResourcesTuning.java b/config-model/src/main/java/com/yahoo/vespa/model/search/NodeResourcesTuning.java
index bc5de959f3f..35211a6a45d 100644
--- a/config-model/src/main/java/com/yahoo/vespa/model/search/NodeResourcesTuning.java
+++ b/config-model/src/main/java/com/yahoo/vespa/model/search/NodeResourcesTuning.java
@@ -17,7 +17,8 @@ public class NodeResourcesTuning implements ProtonConfig.Producer {
     private final static double SUMMARY_FILE_SIZE_AS_FRACTION_OF_MEMORY = 0.02;
     private final static double SUMMARY_CACHE_SIZE_AS_FRACTION_OF_MEMORY = 0.04;
     private final static double MEMORY_GAIN_AS_FRACTION_OF_MEMORY = 0.08;
-    private final static double MIN_MEMORY_PER_FLUSH_THREAD_GB = 12.0;
+    private final static double MIN_MEMORY_PER_FLUSH_THREAD_GB = 16.0;
+    private final static double MAX_FLUSH_TREAD_RATIO = 1.0/8;
     private final static double TLS_SIZE_FRACTION = 0.02;
     final static long MB = 1024 * 1024;
     public final static long GB = MB * 1024;
@@ -96,6 +97,8 @@ public class NodeResourcesTuning implements ProtonConfig.Producer {
         if (usableMemoryGb() < MIN_MEMORY_PER_FLUSH_THREAD_GB) {
             builder.maxconcurrent(1);
         }
+        builder.maxconcurrent(Math.min(builder.build().maxconcurrent(),
+                                       Math.max(1, (int)Math.ceil(resources.vcpu()*MAX_FLUSH_TREAD_RATIO))));
     }
 
     private void tuneFlushStrategyTlsSize(ProtonConfig.Flush.Memory.Builder builder) {