When using multiple threads per search we will never have 100% dutycycle to to the law of Amdahl.

To be on the safe side we ensure that we have enough threads to reach full cpu utilization even with a 0% cuty cycle.

4 files changed, 36 insertions, 2 deletions

diff --git a/config-model/src/main/java/com/yahoo/vespa/model/search/NodeFlavorTuning.java b/config-model/src/main/java/com/yahoo/vespa/model/search/NodeFlavorTuning.java
index 5d8b0b688d8..0998d583d6c 100644
--- a/config-model/src/main/java/com/yahoo/vespa/model/search/NodeFlavorTuning.java
+++ b/config-model/src/main/java/com/yahoo/vespa/model/search/NodeFlavorTuning.java
@@ -18,12 +18,17 @@ public class NodeFlavorTuning implements ProtonConfig.Producer {
     private final Flavor nodeFlavor;
     private final int redundancy;
     private final int searchableCopies;
+    private final int threadsPerSearch;
 
 
     public NodeFlavorTuning(Flavor nodeFlavor, int redundancy, int searchableCopies) {
+        this(nodeFlavor, redundancy, searchableCopies, 1);
+    }
+    public NodeFlavorTuning(Flavor nodeFlavor, int redundancy, int searchableCopies, int threadsPerSearch) {
         this.nodeFlavor = nodeFlavor;
         this.redundancy = redundancy;
         this.searchableCopies = searchableCopies;
+        this.threadsPerSearch = threadsPerSearch;
     }
 
     @Override
@@ -108,8 +113,9 @@ public class NodeFlavorTuning implements ProtonConfig.Producer {
 
     private void tuneRequestThreads(ProtonConfig.Builder builder) {
         int numCores = (int)Math.ceil(nodeFlavor.getMinCpuCores());
-        builder.numsearcherthreads(numCores);
+        builder.numsearcherthreads(numCores*threadsPerSearch);
         builder.numsummarythreads(numCores);
+        builder.numthreadspersearch(threadsPerSearch);
     }
 
     private void tuneWriteFilter(ProtonConfig.Writefilter.Builder builder) {
diff --git a/config-model/src/main/java/com/yahoo/vespa/model/search/SearchNode.java b/config-model/src/main/java/com/yahoo/vespa/model/search/SearchNode.java
index a174e7c38e8..373c62c2eda 100644
--- a/config-model/src/main/java/com/yahoo/vespa/model/search/SearchNode.java
+++ b/config-model/src/main/java/com/yahoo/vespa/model/search/SearchNode.java
@@ -272,7 +272,9 @@ public class SearchNode extends AbstractService implements
         }
         if (getHostResource() != null && getHostResource().getFlavor().isPresent()) {
             Flavor nodeFlavor = getHostResource().getFlavor().get();
-            NodeFlavorTuning nodeFlavorTuning = new NodeFlavorTuning(nodeFlavor, redundancy, searchableCopies);
+            NodeFlavorTuning nodeFlavorTuning = tuning.isPresent()
+                    ? new NodeFlavorTuning(nodeFlavor, redundancy, searchableCopies, tuning.get().getNumThreadsPerSearch())
+                    : new NodeFlavorTuning(nodeFlavor, redundancy, searchableCopies);
             nodeFlavorTuning.getConfig(builder);
 
             if (tuning.isPresent()) {
diff --git a/config-model/src/main/java/com/yahoo/vespa/model/search/Tuning.java b/config-model/src/main/java/com/yahoo/vespa/model/search/Tuning.java
index f93bf6fc872..5984aad7f16 100644
--- a/config-model/src/main/java/com/yahoo/vespa/model/search/Tuning.java
+++ b/config-model/src/main/java/com/yahoo/vespa/model/search/Tuning.java
@@ -406,4 +406,11 @@ public class Tuning extends AbstractConfigProducer implements ProtonConfig.Produ
         if (searchNode != null) searchNode.getConfig(builder);
     }
 
+    public int getNumThreadsPerSearch() {
+        if (searchNode == null) return 1;
+        if (searchNode.threads == null) return 1;
+        if (searchNode.threads.numThreadsPerSearch == null) return 1;
+        return searchNode.threads.numThreadsPerSearch;
+    }
+
 }
diff --git a/config-model/src/test/java/com/yahoo/vespa/model/search/NodeFlavorTuningTest.java b/config-model/src/test/java/com/yahoo/vespa/model/search/NodeFlavorTuningTest.java
index 78c6d2eacc9..023b7249939 100644
--- a/config-model/src/test/java/com/yahoo/vespa/model/search/NodeFlavorTuningTest.java
+++ b/config-model/src/test/java/com/yahoo/vespa/model/search/NodeFlavorTuningTest.java
@@ -73,6 +73,15 @@ public class NodeFlavorTuningTest {
         ProtonConfig cfg = configFromNumCoresSetting(4.5);
         assertEquals(5, cfg.numsearcherthreads());
         assertEquals(5, cfg.numsummarythreads());
+        assertEquals(1, cfg.numthreadspersearch());
+    }
+
+    @Test
+    public void require_that_num_search_threads_and_considers_explict_num_threads_per_search() {
+        ProtonConfig cfg = configFromNumCoresSetting(4.5, 3);
+        assertEquals(15, cfg.numsearcherthreads());
+        assertEquals(5, cfg.numsummarythreads());
+        assertEquals(3, cfg.numthreadspersearch());
     }
 
     @Test
@@ -206,6 +215,10 @@ public class NodeFlavorTuningTest {
         return getConfig(new FlavorsConfig.Flavor.Builder().minCpuCores(numCores));
     }
 
+    private static ProtonConfig configFromNumCoresSetting(double numCores, int numThreadsPerSearch) {
+        return getConfig(new FlavorsConfig.Flavor.Builder().minCpuCores(numCores), new ProtonConfig.Builder(), 1, 1, numThreadsPerSearch);
+    }
+
     private static ProtonConfig configFromEnvironmentType(boolean docker) {
         String environment = (docker ? "DOCKER_CONTAINER" : "undefined");
         return getConfig(new FlavorsConfig.Flavor.Builder().environment(environment));
@@ -223,5 +236,11 @@ public class NodeFlavorTuningTest {
         tuning.getConfig(protonBuilder);
         return new ProtonConfig(protonBuilder);
     }
+    private static ProtonConfig getConfig(FlavorsConfig.Flavor.Builder flavorBuilder, ProtonConfig.Builder protonBuilder, int redundancy, int searchableCopies, int numThreadsPerSearch) {
+        flavorBuilder.name("my_flavor");
+        NodeFlavorTuning tuning = new NodeFlavorTuning(new Flavor(new FlavorsConfig.Flavor(flavorBuilder)), redundancy, searchableCopies, numThreadsPerSearch);
+        tuning.getConfig(protonBuilder);
+        return new ProtonConfig(protonBuilder);
+    }
 
 }