[CalendarServer-changes] [12237] twext/trunk/twext/application/masterchild.py

[source_changes at macosforge.org]

Revision: 12237
          http://trac.calendarserver.org//changeset/12237
Author:   wsanchez at apple.com
Date:     2014-01-03 15:33:05 -0800 (Fri, 03 Jan 2014)
Log Message:
-----------
Span more children as needed.

Modified Paths:
--------------
    twext/trunk/twext/application/masterchild.py

Modified: twext/trunk/twext/application/masterchild.py
===================================================================
--- twext/trunk/twext/application/masterchild.py	2014-01-03 22:12:36 UTC (rev 12236)
+++ twext/trunk/twext/application/masterchild.py	2014-01-03 23:33:05 UTC (rev 12237)
@@ -327,14 +327,24 @@
     pluginName = b"child"
 
 
-    def __init__(self, dispatcher, maxProcessCount=8):
+    def __init__(
+        self, dispatcher, maxProcessCount=8, highWaterMark=3
+    ):
         """
-        @param protocol: The name of the protocol for the child to use
-            to handle connections.
-        @type protocol: L{str} naming an L{IProtocol} implementer.
+        @param dispatcher: The dispatcher managing inbound connections.
+        @type dispatcher: L{InheritedSocketDispatcher}
+
+        @param maxProcessCount: The maximum number of child processes that may
+            be spawned.
+        @type maxProcessCount: L{int}
+
+        @param highWaterMark: The high-end number of connections that each
+            process should be given before new processes should be spawned.
+        @type highWaterMark: L{int}
         """
         self.dispatcher = dispatcher
         self.maxProcessCount = maxProcessCount
+        self.highWaterMark = highWaterMark
 
 
     def startService(self):
@@ -347,16 +357,44 @@
         del(self.children)
 
 
+    def totalEffectiveLoad(self):
+        """
+        Compute the sum of the effective load of all child process.
+
+        @return: The total effective load accross all processes.
+        @rtype: L{float}
+        """
+        return sum(s.effectiveLoad() for s in self.dispatcher.statuses)
+
+
     def socketWillArriveForProtocol(self, protocolName):
         """
         This method is where this service makes sure that there are
         sufficient child processes available to handle additional
         connections.
         """
-        if len(self.children) == 0:
+        numChildren = len(self.children)
+
+        if numChildren == 0:
+            self.log.info("Spawning first child.")
             self.spawnChild(protocolName)
+            return
 
+        totalLoad = self.totalEffectiveLoad()
+        averageLoad = float(totalLoad) / float(numChildren)
 
+        # self.log.info(
+        #     "Load: {totalLoad} / {childCount} = {averageLoad}",
+        #     totalLoad=totalLoad,
+        #     childCount=numChildren,
+        #     averageLoad=averageLoad,
+        # )
+
+        if averageLoad >= self.highWaterMark:
+            if numChildren < self.maxProcessCount:
+                self.spawnChild(protocolName)
+
+
     def spawnChild(self, protocolName):
         """
         Spawn a child process to handle connections.
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