fix: properly compute mW

backend/src/main/java/net/laprun/sustainability/power/sensors/linux/rapl/IntelRAPLSensor.java

@@ -117,11 +117,12 @@ private double computePowerInMilliWatts(int componentIndex, long sensorValue, lo
                 lastUpdateEpoch());
     }
 
-    static double computePowerInMilliWatts(long newValue, long prevValue, long newMeasureTime, long prevMeasureTime) {
-        assert newValue > prevValue : "RAPL overflow occurred, need to deal with it!";
-        assert newMeasureTime > prevMeasureTime : "Not enough time elapsed between measures or order of times problem";
-        final var msBetweenMeasures = newMeasureTime - prevMeasureTime;
-        return (double) (newValue - prevValue) / msBetweenMeasures / 1000;
+    static double computePowerInMilliWatts(long newMicroJoules, long prevMicroJoules, long newMeasureTimeMS,
+            long prevMeasureTimeMS) {
+        assert newMicroJoules > prevMicroJoules : "RAPL overflow occurred, need to deal with it!";
+        assert newMeasureTimeMS > prevMeasureTimeMS : "Not enough time elapsed between measures or order of times problem";
+        final var msBetweenMeasures = newMeasureTimeMS - prevMeasureTimeMS;
+        return (double) (newMicroJoules - prevMicroJoules) / msBetweenMeasures;
     }
 
     @Override

backend/src/test/java/net/laprun/sustainability/power/sensors/linux/rapl/IntelRAPLSensorTest.java

@@ -76,7 +76,7 @@ public String contentAsString() {
     @Test
     void basicWattComputationShouldWork() {
         final var power = IntelRAPLSensor.computePowerInMilliWatts(200, 100, 2000, 1000);
-        assertEquals((double) 100 / 1000 / 1000, power);
+        assertEquals((double) 100 / 1000, power);
     }
 
     private static class TestIntelRAPLSensor extends IntelRAPLSensor {
@@ -107,7 +107,7 @@ void wattComputationShouldWork() throws Exception {
         assertEquals(1, components.length);
         assertEquals(2, raplFile.callCount());
         final var interval = raplFile.measureTimeFor(1) - raplFile.measureTimeFor(0);
-        final var expected = (double) (raplFile.valueAt(1) - raplFile.valueAt(0)) / interval / 1000;
+        final var expected = (double) (raplFile.valueAt(1) - raplFile.valueAt(0)) / interval;
         assertEquals(expected, components[0]);
     }
 

cli/src/main/java/net/laprun/sustainability/cli/Power.java

@@ -100,7 +100,7 @@ private Measure extractPowerConsumption(String applicationName) {
 
     private class ExternalProcessHandler extends BaseProcessHandler {
         private long startTime;
-        private long duration;
+        private long endTime;
 
         public ExternalProcessHandler(String cmd) {
             super("/bin/sh", "-c", stripped(cmd).orElseThrow());
@@ -119,13 +119,13 @@ public void onExit(int statusCode) {
             try {
                 super.onExit(statusCode);
             } finally {
-                duration = System.currentTimeMillis() - this.startTime;
+                endTime = System.currentTimeMillis();
                 measurer.stop();
             }
         }
 
         public long duration() {
-            return duration;
+            return endTime - startTime;
         }
 
         private static Optional<String> stripped(String s) {