net: track state of setNoDelay() and prevent unnecessary system calls

The state of .setNoDelay() is now tracked and code will prevent repeated system calls to setsockopt() when the value has already been set to the desired value for the socket. Change and expand the appropriate test. PR-URL: #31543 Reviewed-By: James M Snell <[email protected]> Reviewed-By: Rich Trott <[email protected]> Reviewed-By: Luigi Pinca <[email protected]>
nodejs · Feb 17, 2020 · 5982726 · 5982726
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commit 5982726
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Showing 2 changed files with 17 additions and 5 deletions.
diff --git a/lib/net.js b/lib/net.js
@@ -257,7 +257,7 @@ function initSocketHandle(self) {
 
 const kBytesRead = Symbol('kBytesRead');
 const kBytesWritten = Symbol('kBytesWritten');
-
+const kSetNoDelay = Symbol('kSetNoDelay');
 
 function Socket(options) {
   if (!(this instanceof Socket)) return new Socket(options);
@@ -271,6 +271,7 @@ function Socket(options) {
   this[kHandle] = null;
   this._parent = null;
   this._host = null;
+  this[kSetNoDelay] = false;
   this[kLastWriteQueueSize] = 0;
   this[kTimeout] = null;
   this[kBuffer] = null;
@@ -487,8 +488,11 @@ Socket.prototype.setNoDelay = function(enable) {
   }
 
   // Backwards compatibility: assume true when `enable` is omitted
-  if (this._handle.setNoDelay)
-    this._handle.setNoDelay(enable === undefined ? true : !!enable);
+  const newValue = enable === undefined ? true : !!enable;
+  if (this._handle.setNoDelay && newValue !== this[kSetNoDelay]) {
+    this[kSetNoDelay] = newValue;
+    this._handle.setNoDelay(newValue);
+  }
 
   return this;
 };

diff --git a/test/parallel/test-net-socket-setnodelay.js b/test/parallel/test-net-socket-setnodelay.js
@@ -20,18 +20,26 @@ socket.setNoDelay();
 
 socket = new net.Socket({
   handle: {
-    setNoDelay: common.mustCall(genSetNoDelay(true), truthyValues.length)
+    setNoDelay: common.mustCall(genSetNoDelay(true), 1)
   }
 });
 truthyValues.forEach((testVal) => socket.setNoDelay(testVal));
 
 socket = new net.Socket({
   handle: {
-    setNoDelay: common.mustCall(genSetNoDelay(false), falseyValues.length)
+    setNoDelay: common.mustNotCall()
   }
 });
 falseyValues.forEach((testVal) => socket.setNoDelay(testVal));
 
+socket = new net.Socket({
+  handle: {
+    setNoDelay: common.mustCall(() => {}, 3)
+  }
+});
+truthyValues.concat(falseyValues).concat(truthyValues)
+  .forEach((testVal) => socket.setNoDelay(testVal));
+
 // If a handler doesn't have a setNoDelay function it shouldn't be called.
 // In the case below, if it is called an exception will be thrown
 socket = new net.Socket({