kezhenxu94 commented on a change in pull request #2930: One more time for
heigher performance
URL: https://github.com/apache/skywalking/pull/2930#discussion_r296446485
##########
File path:
apm-commons/apm-datacarrier/src/main/java/org/apache/skywalking/apm/commons/datacarrier/common/AtomicRangeInteger.java
##########
@@ -18,23 +18,32 @@
package org.apache.skywalking.apm.commons.datacarrier.common;
-
import java.io.Serializable;
import java.util.concurrent.atomic.AtomicInteger;
/**
- * Created by wusheng on 2016/10/25.
+ * Created by lkxiaolou on 2019/06/22.
*/
public class AtomicRangeInteger extends Number implements Serializable {
private static final long serialVersionUID = -4099792402691141643L;
+
+ /**
+ * please dont't change the left and right Placeholders
+ * to disable false-sharing for more performance
+ */
+ private int[] leftPlaceholders;
private AtomicInteger value;
+ private int[] rightPlaceholders;
+
private int startValue;
private int endValue;
public AtomicRangeInteger(int startValue, int maxValue) {
this.value = new AtomicInteger(startValue);
this.startValue = startValue;
this.endValue = maxValue - 1;
+ leftPlaceholders = new int[15];
+ rightPlaceholders = new int[15];
Review comment:
> sorry, I have make some tests to find my first version is right. so I'm
roll back the code.
> Use an array ensure the value load in CPU's cache and cached in one line
without other variable.
>
> We can learn the Disruptor how to do this in this article
>
> https://tech.meituan.com/2016/11/18/disruptor.html
>
> The Unsafe is used in the Disruptor, and it worked well. So we don't worry
about Unsafe will change in the future.
@wu-sheng the unsafe is also used in netty too, I don't think it's a concern
herr
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