hadoop之MapReduce框架TaskTracker端心跳机制分析(源码分析第六篇)
/*** Main service loop.Will stay in this loop forever.
*/
State offerService() throws Exception {
long lastHeartbeat = System.currentTimeMillis();//上一次发心跳距现在时间
////此循环主要根据控制完成task个数控制心跳间隔。
while (running && !shuttingDown) {
try {
long now = System.currentTimeMillis();//获得当前时间
// accelerate to account for multiple finished tasks up-front
//通过完成的任务数动态控制心跳间隔时间
long remaining =
(lastHeartbeat + getHeartbeatInterval(finishedCount.get())) - now;
while (remaining > 0) {
// sleeps for the wait time or
// until there are *enough* empty slots to schedule tasks
synchronized (finishedCount) {
finishedCount.wait(remaining);
// Recompute
now = System.currentTimeMillis();
remaining =
(lastHeartbeat + getHeartbeatInterval(finishedCount.get())) - now;
if (remaining
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