PROSAGA码农传奇-zookeeper-Zookeeper zk_max

<pre><code> 该 `zk_max|avg|min_latency` 度量从ZK服务器启动开始计算。
</code></pre>该 <code>mntr</code> 命令由。处理 MonitorCommand ，查询来自的max / avg / min请求指标 ZooKeeperServer.serverStats.requestLatency 
<pre><code>ZKDatabase zkdb = zkServer.getZKDatabase();
ServerStats stats = zkServer.serverStats();

print("version", Version.getFullVersion());

print("avg_latency", stats.getAvgLatency());
print("max_latency", stats.getMaxLatency());
print("min_latency", stats.getMinLatency());
</code></pre>ServerStats.java
<pre><code>// getters
public long getMinLatency() {
 return requestLatency.getMin();
}

public double getAvgLatency() {
    return requestLatency.getAvg();
}

public long getMaxLatency() {
 return requestLatency.getMax();
}
</code></pre>并且请求延迟在更新时更新 ServerStats.updateLatency（） 。核心实现类是 AvgMinMaxCounter 。
<pre><code>public void updateLatency(Request request, long currentTime) {
 long latency = currentTime - request.createTime;
 if (latency < 0) {
 return;
 }
 requestLatency.addDataPoint(latency);
 if (request.getHdr() != null) {
 // Only quorum request should have header
 ServerMetrics.UPDATE_LATENCY.add(latency);
 } else {
 // All read request should goes here
 ServerMetrics.READ_LATENCY.add(latency);
 }
}
</code></pre>

Zookeeper zk_max_latency是如何计算的？