Transport threads and _hot_threads

docs/changelog/90482.yaml

@@ -0,0 +1,6 @@
+pr: 90482
+summary: Transport threads and `_hot_threads`
+area: Infra/Core
+type: enhancement
+issues:
+ - 90334

server/src/main/java/org/elasticsearch/monitor/jvm/HotThreads.java

@@ -15,6 +15,7 @@
 import org.elasticsearch.common.unit.ByteSizeValue;
 import org.elasticsearch.common.util.Maps;
 import org.elasticsearch.core.TimeValue;
+import org.elasticsearch.transport.Transports;
 
 import java.lang.management.ManagementFactory;
 import java.lang.management.ThreadInfo;
@@ -313,12 +314,15 @@ String innerDetect(ThreadMXBean threadBean, SunThreadInfo sunThreadInfo, long cu
                 case CPU -> {
                     double percentCpu = getTimeSharePercentage(topThread.getCpuTime());
                     double percentOther = getTimeSharePercentage(topThread.getOtherTime());
+                    double percentTotal = (Transports.isTransportThread(threadName)) ? percentCpu : percentOther + percentCpu;
+                    String otherLabel = (Transports.isTransportThread(threadName)) ? "idle" : "other";
                     sb.append(
                         String.format(
                             Locale.ROOT,
-                            "%n%4.1f%% [cpu=%1.1f%%, other=%1.1f%%] (%s out of %s) %s usage by thread '%s'%n",
-                            percentOther + percentCpu,
+                            "%n%4.1f%% [cpu=%1.1f%%, %s=%1.1f%%] (%s out of %s) %s usage by thread '%s'%n",
+                            percentTotal,
                             percentCpu,
+                            otherLabel,
                             percentOther,
                             TimeValue.timeValueNanos(topThread.getCpuTime() + topThread.getOtherTime()),
                             interval,
@@ -412,8 +416,8 @@ static int similarity(ThreadInfo threadInfo, ThreadInfo threadInfo0) {
 
     static class ThreadTimeAccumulator {
         private final long threadId;
+        private final String threadName;
         private final TimeValue interval;
-
         private long cpuTime;
         private long blockedTime;
         private long waitedTime;
@@ -425,6 +429,7 @@ static class ThreadTimeAccumulator {
             this.cpuTime = cpuTime;
             this.allocatedBytes = allocatedBytes;
             this.threadId = info.getThreadId();
+            this.threadName = info.getThreadName();
             this.interval = interval;
         }
 
@@ -457,6 +462,8 @@ public long getRunnableTime() {
             // not running, or it has been asleep forever.
             if (getCpuTime() == 0) {
                 return 0;
+            } else if (Transports.isTransportThread(threadName)) {
+                return getCpuTime();
             }
             return Math.max(interval.nanos() - getWaitedTime() - getBlockedTime(), 0);
         }
@@ -468,7 +475,7 @@ public long getOtherTime() {
                 return 0;
             }
 
-            return Math.max(getRunnableTime() - getCpuTime(), 0);
+            return Math.max(interval.nanos() - getWaitedTime() - getBlockedTime() - getCpuTime(), 0);
         }
 
         public long getBlockedTime() {

server/src/main/java/org/elasticsearch/transport/Transports.java

@@ -36,7 +36,16 @@ public enum Transports {
      * networking threads.
      */
     public static boolean isTransportThread(Thread t) {
-        final String threadName = t.getName();
+        return isTransportThread(t.getName());
+    }
+
+    /**
+     * Utility method to detect whether a thread is a network thread. Typically
+     * used in assertions to make sure that we do not call blocking code from
+     * networking threads.
+     * @param threadName the name of the thread
+     */
+    public static boolean isTransportThread(String threadName) {
         for (String s : TRANSPORT_THREAD_NAMES) {
             if (threadName.contains(s)) {
                 return true;