From ba44eb11602dbd0625de46b11c56089aec217577 Mon Sep 17 00:00:00 2001
From: Michael Peter Christen <mc@yacy.net>
Date: Thu, 16 Jan 2014 17:34:26 +0100
Subject: [PATCH] when scaling the number of remote peers, also consider the
 machine load and the number of cores

---
 source/net/yacy/cora/util/Memory.java   | 8 ++++++++
 source/net/yacy/peers/RemoteSearch.java | 4 ++++
 2 files changed, 12 insertions(+)

diff --git a/source/net/yacy/cora/util/Memory.java b/source/net/yacy/cora/util/Memory.java
index 33b483206..569e72c55 100644
--- a/source/net/yacy/cora/util/Memory.java
+++ b/source/net/yacy/cora/util/Memory.java
@@ -66,6 +66,14 @@ public class Memory {
     public static final long used() {
         return total() - free();
     }
+
+    /**
+     * get number of CPU cores
+     * @return number of CPU cores
+     */
+    public static final long cores() {
+        return runtime.availableProcessors();
+    }
     
     /**
      * get the system load within the last minute
diff --git a/source/net/yacy/peers/RemoteSearch.java b/source/net/yacy/peers/RemoteSearch.java
index 08e24cea0..f316a768f 100644
--- a/source/net/yacy/peers/RemoteSearch.java
+++ b/source/net/yacy/peers/RemoteSearch.java
@@ -34,6 +34,7 @@ import org.apache.solr.client.solrj.SolrQuery;
 import net.yacy.cora.document.encoding.ASCII;
 import net.yacy.cora.storage.HandleSet;
 import net.yacy.cora.util.ConcurrentLog;
+import net.yacy.cora.util.Memory;
 import net.yacy.kelondro.util.MemoryControl;
 import net.yacy.repository.Blacklist;
 import net.yacy.search.Switchboard;
@@ -145,6 +146,9 @@ public class RemoteSearch extends Thread {
         int redundancy = event.peers.redundancy();
         if (indexingQueueSize > 10) redundancy = Math.max(1, redundancy - 1);
         if (indexingQueueSize > 50) redundancy = Math.max(1, redundancy - 1);
+        if (Memory.load() > 2.0) redundancy = Math.max(1, redundancy - 1);
+        if (Memory.cores() < 4) redundancy = Math.max(1, redundancy - 1);
+        if (Memory.cores() == 1) redundancy = 1;
         int minage = 3;
         int robinsoncount = event.peers.scheme.verticalPartitions() * redundancy / 2;
         if (indexingQueueSize > 10) robinsoncount = Math.max(1, robinsoncount / 2);