svn commit: r1213775 - in /cassandra/branches/cassandra-1.0: CHANGES.txt src/java/org/apache/cassandra/utils/obs/OpenBitSet.java

[jbellis]

Author: jbellis
Date: Tue Dec 13 16:38:12 2011
New Revision: 1213775

URL: http://svn.apache.org/viewvc?rev=1213775&view=rev
Log:
more efficient allocation of small bloom filters
patch by slebresne; reviewed by jbellis for CASSANDRA-3618

Modified:
    cassandra/branches/cassandra-1.0/CHANGES.txt
    
cassandra/branches/cassandra-1.0/src/java/org/apache/cassandra/utils/obs/OpenBitSet.java

Modified: cassandra/branches/cassandra-1.0/CHANGES.txt
URL: 
http://svn.apache.org/viewvc/cassandra/branches/cassandra-1.0/CHANGES.txt?rev=1213775&r1=1213774&r2=1213775&view=diff
==============================================================================
--- cassandra/branches/cassandra-1.0/CHANGES.txt (original)
+++ cassandra/branches/cassandra-1.0/CHANGES.txt Tue Dec 13 16:38:12 2011
@@ -1,5 +1,6 @@
 1.0.7
  * fix assertion when dropping a columnfamily with no sstables (CASSANDRA-3614)
+ * more efficient allocation of small bloom filters (CASSANDRA-3618)
 
 
 1.0.6

Modified: 
cassandra/branches/cassandra-1.0/src/java/org/apache/cassandra/utils/obs/OpenBitSet.java
URL: 
http://svn.apache.org/viewvc/cassandra/branches/cassandra-1.0/src/java/org/apache/cassandra/utils/obs/OpenBitSet.java?rev=1213775&r1=1213774&r2=1213775&view=diff
==============================================================================
--- 
cassandra/branches/cassandra-1.0/src/java/org/apache/cassandra/utils/obs/OpenBitSet.java
 (original)
+++ 
cassandra/branches/cassandra-1.0/src/java/org/apache/cassandra/utils/obs/OpenBitSet.java
 Tue Dec 13 16:38:12 2011
@@ -76,6 +76,7 @@ Test system: AMD Opteron, 64 bit linux, 
 public class OpenBitSet implements Serializable {
   protected long[][] bits;
   protected int wlen;   // number of words (elements) used in the array
+  private final int pageCount;
   /**
    * length of bits[][] page in long[] elements. 
    * Choosing unform size for all sizes of bitsets fight fragmentation for 
very large
@@ -95,13 +96,19 @@ public class OpenBitSet implements Seria
   public OpenBitSet(long numBits, boolean allocatePages) 
   {
     wlen= bits2words(numBits);    
+    int lastPageSize = wlen % PAGE_SIZE;
+    int fullPageCount = wlen / PAGE_SIZE;
+    pageCount = fullPageCount + (lastPageSize == 0 ? 0 : 1);
     
-    bits = new long[getPageCount()][];
-    
+    bits = new long[pageCount][];
+
     if (allocatePages)
     {
-        for (int allocated=0,i=0;allocated<wlen;allocated+=PAGE_SIZE,i++)
-            bits[i]=new long[PAGE_SIZE];
+        for (int i = 0; i < fullPageCount; ++i)
+            bits[i] = new long[PAGE_SIZE];
+
+        if (lastPageSize != 0)
+            bits[bits.length - 1] = new long[lastPageSize];
     }
   }
 
@@ -119,7 +126,7 @@ public class OpenBitSet implements Seria
   
   public int getPageCount()
   {
-      return wlen / PAGE_SIZE + 1;
+      return pageCount;
   }
 
   public long[] getPage(int pageIdx)