Darrel Schneider created GEODE-6889:
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Summary: replyWaitMaxTime stat calculation code needs improvement
Key: GEODE-6889
URL: https://issues.apache.org/jira/browse/GEODE-6889
Project: Geode
Issue Type: Improvement
Components: core
Reporter: Darrel Schneider
The way the replyWaitMaxTime is calculated has some problems:
1. the elapsed time is calculated using System.currentTimeMillis but should
instead use getStatTime (it actually uses getStatTime for the begin timestamp
but not for the end timestamp).
2. a local atomic should be used to calculate it instead of reading the value
from the Statistics instance. Reading is expensive since it uses
synchronization.
The following is a prototype fix for #2 I used when performance testing:
{noformat}
diff --git
a/geode-core/src/main/java/org/apache/geode/distributed/internal/DistributionStats.java
b/geode-core/src/main/java/org/apache/geode/distributed/internal/DistributionStats.java
index 91c47e2495..d591e35570 100644
---
a/geode-core/src/main/java/org/apache/geode/distributed/internal/DistributionStats.java
+++
b/geode-core/src/main/java/org/apache/geode/distributed/internal/DistributionStats.java
@@ -14,6 +14,8 @@
*/
package org.apache.geode.distributed.internal;
+import java.util.concurrent.atomic.AtomicLong;
+
import org.apache.logging.log4j.Logger;
import org.apache.geode.StatisticDescriptor;
@@ -1602,6 +1604,8 @@ public class DistributionStats implements DMStats {
return getStatTime();
}
+ private final AtomicLong replyWaitMaxTime = new AtomicLong();
+
@Override
public void endReplyWait(long startNanos, long initTime) {
if (enableClockStats) {
@@ -1610,8 +1614,17 @@ public class DistributionStats implements DMStats {
}
if (initTime != 0) {
long mswait = System.currentTimeMillis() - initTime;
- if (mswait > getReplyWaitMaxTime()) {
- stats.setLong(replyWaitMaxTimeId, mswait);
+ boolean done = false;
+ while (!done) {
+ long currentReplyWaitMaxTime = replyWaitMaxTime.get();
+ if (mswait > currentReplyWaitMaxTime) {
+ done = replyWaitMaxTime.compareAndSet(currentReplyWaitMaxTime,
mswait);
+ if (done) {
+ stats.setLong(replyWaitMaxTimeId, mswait);
+ }
+ } else {
+ done = true;
+ }
}
}
stats.incInt(replyWaitsInProgressId, -1);{noformat}
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