Add config for minimum worker threads in Jetty

3 files changed, 13 insertions, 2 deletions

diff --git a/jdisc_http_service/abi-spec.json b/jdisc_http_service/abi-spec.json
index 43f68274c2e..c19ce5ce83c 100644
--- a/jdisc_http_service/abi-spec.json
+++ b/jdisc_http_service/abi-spec.json
@@ -741,6 +741,7 @@
       "public com.yahoo.jdisc.http.ServerConfig$Builder filter(com.yahoo.jdisc.http.ServerConfig$Filter$Builder)",
       "public com.yahoo.jdisc.http.ServerConfig$Builder filter(java.util.List)",
       "public com.yahoo.jdisc.http.ServerConfig$Builder maxWorkerThreads(int)",
+      "public com.yahoo.jdisc.http.ServerConfig$Builder minWorkerThreads(int)",
       "public com.yahoo.jdisc.http.ServerConfig$Builder stopTimeout(double)",
       "public com.yahoo.jdisc.http.ServerConfig$Builder jmx(com.yahoo.jdisc.http.ServerConfig$Jmx$Builder)",
       "public com.yahoo.jdisc.http.ServerConfig$Builder metric(com.yahoo.jdisc.http.ServerConfig$Metric$Builder)",
@@ -894,6 +895,7 @@
       "public java.util.List filter()",
       "public com.yahoo.jdisc.http.ServerConfig$Filter filter(int)",
       "public int maxWorkerThreads()",
+      "public int minWorkerThreads()",
       "public double stopTimeout()",
       "public com.yahoo.jdisc.http.ServerConfig$Jmx jmx()",
       "public com.yahoo.jdisc.http.ServerConfig$Metric metric()",
diff --git a/jdisc_http_service/src/main/java/com/yahoo/jdisc/http/server/jetty/JettyHttpServer.java b/jdisc_http_service/src/main/java/com/yahoo/jdisc/http/server/jetty/JettyHttpServer.java
index 303b36430a5..03f29aa7bf3 100644
--- a/jdisc_http_service/src/main/java/com/yahoo/jdisc/http/server/jetty/JettyHttpServer.java
+++ b/jdisc_http_service/src/main/java/com/yahoo/jdisc/http/server/jetty/JettyHttpServer.java
@@ -84,7 +84,7 @@ public class JettyHttpServer extends AbstractServerProvider {
         server.setStopTimeout((long)(serverConfig.stopTimeout() * 1000.0));
         server.setRequestLog(new AccessLogRequestLog(accessLog, serverConfig.accessLog()));
         setupJmx(server, serverConfig);
-        ((QueuedThreadPool)server.getThreadPool()).setMaxThreads(serverConfig.maxWorkerThreads());
+        configureJettyThreadpool(server, serverConfig);
 
         for (ConnectorFactory connectorFactory : connectorFactories.allComponents()) {
             ConnectorConfig connectorConfig = connectorFactory.getConnectorConfig();
@@ -135,6 +135,12 @@ public class JettyHttpServer extends AbstractServerProvider {
         }
     }
 
+    private static void configureJettyThreadpool(Server server, ServerConfig config) {
+        QueuedThreadPool pool = (QueuedThreadPool) server.getThreadPool();
+        pool.setMaxThreads(config.maxWorkerThreads());
+        pool.setMinThreads(config.minWorkerThreads());
+    }
+
     private static JMXServiceURL createJmxLoopbackOnlyServiceUrl(int port) {
         try {
             return new JMXServiceURL("rmi", "localhost", port, "/jndi/rmi://localhost:" + port + "/jmxrmi");
diff --git a/jdisc_http_service/src/main/resources/configdefinitions/jdisc.http.jdisc.http.server.def b/jdisc_http_service/src/main/resources/configdefinitions/jdisc.http.jdisc.http.server.def
index 3118a7dea64..81f9859fabd 100644
--- a/jdisc_http_service/src/main/resources/configdefinitions/jdisc.http.jdisc.http.server.def
+++ b/jdisc_http_service/src/main/resources/configdefinitions/jdisc.http.jdisc.http.server.def
@@ -27,9 +27,12 @@ filter[].id string
 # The binding of a filter
 filter[].binding string
 
-# Max number of threads in pool
+# Max number of threads in underlying Jetty pool
 maxWorkerThreads                      int    default = 200
 
+# Min number of threads in underlying Jetty pool
+minWorkerThreads                      int    default = 8
+
 # Stop timeout in seconds. The maximum allowed time to process in-flight requests during server shutdown. Setting it to 0 disable graceful shutdown.
 stopTimeout                           double default = 30.0