Author: markt
Date: Tue Oct 1 18:43:04 2013
New Revision: 1528176
URL: http://svn.apache.org/r1528176
Log:
Address issue reported with high CPU usage under low load load.
Modified:
tomcat/tc7.0.x/trunk/ (props changed)
tomcat/tc7.0.x/trunk/java/org/apache/tomcat/util/net/AprEndpoint.java
Propchange: tomcat/tc7.0.x/trunk/
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Merged /tomcat/trunk:r1528171
Modified: tomcat/tc7.0.x/trunk/java/org/apache/tomcat/util/net/AprEndpoint.java
URL:
http://svn.apache.org/viewvc/tomcat/tc7.0.x/trunk/java/org/apache/tomcat/util/net/AprEndpoint.java?rev=1528176&r1=1528175&r2=1528176&view=diff
==============================================================================
--- tomcat/tc7.0.x/trunk/java/org/apache/tomcat/util/net/AprEndpoint.java
(original)
+++ tomcat/tc7.0.x/trunk/java/org/apache/tomcat/util/net/AprEndpoint.java Tue
Oct 1 18:43:04 2013
@@ -1274,6 +1274,13 @@ public class AprEndpoint extends Abstrac
protected 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.
*/
protected long pool = 0;
@@ -1361,6 +1368,7 @@ public class AprEndpoint extends Abstrac
pollerCount = defaultPollerSize / actualPollerSize;
pollerTime = pollTime / pollerCount;
+ nextPollerTime = pollerTime;
pollers = new long[pollerCount];
pollers[0] = pollset;
@@ -1735,7 +1743,18 @@ 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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