Author: markt
Date: Tue Oct 1 18:27:42 2013
New Revision: 1528171
URL: http://svn.apache.org/r1528171
Log:
Address issue reported with high CPU usage under low load load.
Modified:
tomcat/trunk/java/org/apache/tomcat/util/net/AprEndpoint.java
Modified: tomcat/trunk/java/org/apache/tomcat/util/net/AprEndpoint.java
URL:
http://svn.apache.org/viewvc/tomcat/trunk/java/org/apache/tomcat/util/net/AprEndpoint.java?rev=1528171&r1=1528170&r2=1528171&view=diff
==============================================================================
--- tomcat/trunk/java/org/apache/tomcat/util/net/AprEndpoint.java (original)
+++ tomcat/trunk/java/org/apache/tomcat/util/net/AprEndpoint.java Tue Oct 1
18:27:42 2013
@@ -1282,6 +1282,13 @@ public class AprEndpoint extends Abstrac
private int pollerTime;
/**
+ * Variable poller timeout that adjusts depending on how many poll sets
+ * are in use so that the total poll time across all poll sets remains
+ * equal to pollTime.
+ */
+ private int nextPollerTime;
+
+ /**
* Root pool.
*/
private long pool = 0;
@@ -1369,6 +1376,7 @@ public class AprEndpoint extends Abstrac
pollerCount = defaultPollerSize / actualPollerSize;
pollerTime = pollTime / pollerCount;
+ nextPollerTime = pollerTime;
pollers = new long[pollerCount];
pollers[0] = pollset;
@@ -1743,7 +1751,18 @@ public class AprEndpoint extends Abstrac
int rv = 0;
// Iterate on each pollers, but no need to poll empty
pollers
if (pollerSpace[i] < actualPollerSize) {
- rv = Poll.poll(pollers[i], pollerTime, desc, true);
+ rv = Poll.poll(pollers[i], nextPollerTime, desc,
true);
+ // Reset the nextPollerTime
+ nextPollerTime = pollerTime;
+ } else {
+ // Skipping an empty poll set means skipping a wait
+ // time of pollerTime microseconds. If most of the
+ // poll sets are skipped then this loop will be
+ // tighter than expected which could lead to higher
+ // than expected CPU usage. Extending the
+ // nextPollerTime ensures that this loop always
+ // takes about the same time to execute.
+ nextPollerTime += pollerTime;
}
if (rv > 0) {
pollerSpace[i] += rv;
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