If there is a lot of memory, allow mor eflush threads.

2 files changed, 7 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 b6a7fb6182e..ee18eceb719 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
@@ -97,8 +97,10 @@ public class NodeResourcesTuning implements ProtonConfig.Producer {
         if (usableMemoryGb() < MIN_MEMORY_PER_FLUSH_THREAD_GB) {
             builder.maxconcurrent(1);
         }
+        double min_concurrent_mem = usableMemoryGb() / (2*MIN_MEMORY_PER_FLUSH_THREAD_GB);
+        double min_concurrent_cpu = resources.vcpu() * MAX_FLUSH_THREAD_RATIO;
         builder.maxconcurrent(Math.min(builder.build().maxconcurrent(),
-                                       Math.max(1, (int)Math.ceil(resources.vcpu()*MAX_FLUSH_THREAD_RATIO))));
+                (int)Math.ceil(Math.max(min_concurrent_mem, min_concurrent_cpu))));
     }
 
     private void tuneFlushStrategyTlsSize(ProtonConfig.Flush.Memory.Builder builder) {
diff --git a/config-model/src/test/java/com/yahoo/vespa/model/search/NodeResourcesTuningTest.java b/config-model/src/test/java/com/yahoo/vespa/model/search/NodeResourcesTuningTest.java
index a6d44d46dcb..9fe38512fc0 100644
--- a/config-model/src/test/java/com/yahoo/vespa/model/search/NodeResourcesTuningTest.java
+++ b/config-model/src/test/java/com/yahoo/vespa/model/search/NodeResourcesTuningTest.java
@@ -183,6 +183,10 @@ public class NodeResourcesTuningTest {
     @Test
     public void require_that_concurrent_flush_threads_is_1_with_low_memory() {
         assertEquals(2, fromMemAndCpu(17, 9).flush().maxconcurrent());
+        assertEquals(2, fromMemAndCpu(17, 64).flush().maxconcurrent()); // still capped by max
+        assertEquals(2, fromMemAndCpu(65, 8).flush().maxconcurrent()); // still capped by max
+        assertEquals(2, fromMemAndCpu(33, 8).flush().maxconcurrent());
+        assertEquals(1, fromMemAndCpu(31, 8).flush().maxconcurrent());
         assertEquals(1, fromMemAndCpu(15, 8).flush().maxconcurrent());
         assertEquals(1, fromMemAndCpu(17, 8).flush().maxconcurrent());
         assertEquals(1, fromMemAndCpu(15, 8).flush().maxconcurrent());