Add javadoc and simplify method

4 files changed, 16 insertions, 8 deletions

diff --git a/docker-api/src/main/java/com/yahoo/vespa/hosted/dockerapi/ContainerResources.java b/docker-api/src/main/java/com/yahoo/vespa/hosted/dockerapi/ContainerResources.java
index 70ba58cd9cf..bd8ffb0163c 100644
--- a/docker-api/src/main/java/com/yahoo/vespa/hosted/dockerapi/ContainerResources.java
+++ b/docker-api/src/main/java/com/yahoo/vespa/hosted/dockerapi/ContainerResources.java
@@ -9,7 +9,7 @@ import java.util.Objects;
 public class ContainerResources {
 
     public static final ContainerResources UNLIMITED = ContainerResources.from(0, 0, 0);
-    private static final int CPU_PERIOD = 100_000; // 100 µs
+    public static final int CPU_PERIOD_US = 100_000; // 100 ms
 
     /**
      * Hard limit on container's CPU usage: Implemented using Completely Fair Scheduler (CFS) by allocating a given
@@ -65,11 +65,12 @@ public class ContainerResources {
     // Although docker allows to update cpu quota to 0, this is not a legal value, must be set -1 for unlimited
     // See: https://github.com/docker/for-linux/issues/558
     public int cpuQuota() {
-        return cpus > 0 ? (int) (cpus * CPU_PERIOD) : -1;
+        return cpus > 0 ? (int) (cpus * CPU_PERIOD_US) : -1;
     }
 
+    /** Duration (in µs) of a single period used as the basis for process scheduling */
     public int cpuPeriod() {
-        return CPU_PERIOD;
+        return CPU_PERIOD_US;
     }
 
     public int cpuShares() {
diff --git a/docker-api/src/main/java/com/yahoo/vespa/hosted/dockerapi/ContainerStats.java b/docker-api/src/main/java/com/yahoo/vespa/hosted/dockerapi/ContainerStats.java
index 7fbe47b011c..797dffdef1f 100644
--- a/docker-api/src/main/java/com/yahoo/vespa/hosted/dockerapi/ContainerStats.java
+++ b/docker-api/src/main/java/com/yahoo/vespa/hosted/dockerapi/ContainerStats.java
@@ -111,14 +111,20 @@ public class ContainerStats {
         }
 
         public int getOnlineCpus() { return this.onlineCpus; }
+
+        /** Total CPU time (in ns) spent executing all the processes on this host */
         public long getSystemCpuUsage() { return this.systemCpuUsage; }
+
+        /** Total CPU time (in ns) spent running all the processes in this container */
         public long getTotalUsage() { return totalUsage; }
+
+        /** Total CPU time (in ns) spent in kernel mode while executing processes in this container */
         public long getUsageInKernelMode() { return usageInKernelMode; }
 
-        /** Total CPU time processes in this container were throttled for */
+        /** Total CPU time (in ns) processes in this container were throttled for */
         public long getThrottledTime() { return throttledTime; }
 
-        /** Number of periods when throttling enabled for this container */
+        /** Number of periods with throttling enabled for this container */
         public long getThrottlingActivePeriods() { return throttlingActivePeriods; }
 
         /** Number of periods this container hit the throttling limit */
diff --git a/node-admin/src/main/java/com/yahoo/vespa/hosted/node/admin/nodeagent/NodeAgentImpl.java b/node-admin/src/main/java/com/yahoo/vespa/hosted/node/admin/nodeagent/NodeAgentImpl.java
index 3a9eae45607..4bf361e0e56 100644
--- a/node-admin/src/main/java/com/yahoo/vespa/hosted/node/admin/nodeagent/NodeAgentImpl.java
+++ b/node-admin/src/main/java/com/yahoo/vespa/hosted/node/admin/nodeagent/NodeAgentImpl.java
@@ -623,6 +623,7 @@ public class NodeAgentImpl implements NodeAgent {
 
     class CpuUsageReporter {
         private static final double BILLION = 1_000_000_000d;
+        private static final double PERIOD_IN_SECONDS = ContainerResources.CPU_PERIOD_US / 1_000_000d;
         private long containerKernelUsage = 0;
         private long totalContainerUsage = 0;
         private long totalSystemUsage = 0;
@@ -667,11 +668,11 @@ public class NodeAgentImpl implements NodeAgent {
         }
 
         double getThrottledTime() {
-            return deltaSystemUsage == 0 ? Double.NaN : 60d * deltaThrottledPeriods / deltaThrottlingActivePeriods;
+            return deltaThrottlingActivePeriods == 0 ? Double.NaN : deltaThrottledPeriods * PERIOD_IN_SECONDS;
         }
 
         double getThrottledCpuTime() {
-            return deltaSystemUsage == 0 ? Double.NaN : deltaThrottledTime / BILLION;
+            return deltaThrottlingActivePeriods == 0 ? Double.NaN : deltaThrottledTime / BILLION;
         }
     }
 
diff --git a/node-admin/src/test/resources/expected.container.system.metrics.txt b/node-admin/src/test/resources/expected.container.system.metrics.txt
index 4876466d8ca..9f32be2a0c9 100644
--- a/node-admin/src/test/resources/expected.container.system.metrics.txt
+++ b/node-admin/src/test/resources/expected.container.system.metrics.txt
@@ -11,7 +11,7 @@ s:
     "metrics": {
         "cpu.sys.util": 3.402,
         "cpu.throttled_cpu_time": 290.0,
-        "cpu.throttled_time": 49.473,
+        "cpu.throttled_time": 47.0,
         "cpu.util": 5.4,
         "cpu.vcpus": 2.0,
         "disk.limit": 250000000000,