Cap total number of search threads to num-cores *4 rounded up to closes multiple of threads-per-search.

2 files changed, 11 insertions, 2 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 495395db71b..b6a7fb6182e 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
@@ -121,7 +121,7 @@ public class NodeResourcesTuning implements ProtonConfig.Producer {
 
     private void tuneRequestThreads(ProtonConfig.Builder builder) {
         int numCores = (int)Math.ceil(resources.vcpu());
-        builder.numsearcherthreads(numCores*threadsPerSearch);
+        builder.numsearcherthreads(Math.min(((numCores*4 + threadsPerSearch - 1)/threadsPerSearch)*threadsPerSearch, numCores*threadsPerSearch));
         builder.numsummarythreads(numCores);
         builder.numthreadspersearch(threadsPerSearch);
     }
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 d0fa205237e..a6d44d46dcb 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
@@ -85,7 +85,7 @@ public class NodeResourcesTuningTest {
     }
 
     @Test
-    void require_that_num_search_threads_and_considers_explict_num_threads_per_search() {
+    void require_that_num_search_threads_considers_explict_num_threads_per_search() {
         ProtonConfig cfg = configFromNumCoresSetting(4.5, 3);
         assertEquals(15, cfg.numsearcherthreads());
         assertEquals(5, cfg.numsummarythreads());
@@ -93,6 +93,15 @@ public class NodeResourcesTuningTest {
     }
 
     @Test
+    void require_that_num_search_threads_can_only_have_4x_overcommit_rounded_up_to_num_threads_per_search() {
+        ProtonConfig cfg = configFromNumCoresSetting(9, 8);
+        assertEquals(40, cfg.numsearcherthreads());
+        assertEquals(9, cfg.numsummarythreads());
+        assertEquals(8, cfg.numthreadspersearch());
+    }
+
+
+    @Test
     void require_that_fast_disk_is_reflected_in_proton_config() {
         ProtonConfig cfg = configFromDiskSetting(true);
         assertEquals(200, cfg.hwinfo().disk().writespeed(), delta);