fix: adjust sampling frequency to account for processing time

runtime/src/main/java/io/quarkiverse/power/runtime/sensors/macos/powermetrics/MacOSPowermetricsSensor.java

@@ -48,8 +48,7 @@ AppleSiliconMeasure extractPowerMeasure(InputStream powerMeasureInput, long pid)
                 true);
     }
 
-    AppleSiliconMeasure extractPowerMeasure(OngoingPowerMeasure ongoingMeasure,
-            InputStream powerMeasureInput,
+    AppleSiliconMeasure extractPowerMeasure(OngoingPowerMeasure ongoingMeasure, InputStream powerMeasureInput,
             String paddedPIDAsString, boolean returnCurrent) {
         try {
             // Should not be closed since it closes the process
@@ -124,10 +123,10 @@ private static double extractAttributedMeasure(String line, double attributionRa
 
     @Override
     public OngoingPowerMeasure start(long duration, long frequency) throws Exception {
-        final var freq = Long.toString(Math.round(frequency));
+        // it takes some time for the external process in addition to the sampling time so adjust the sampling frequency to account for this so that at most one measure occurs during the sampling time window
+        final var freq = Long.toString(frequency - 50);
         powermetrics = Runtime.getRuntime()
-                .exec("sudo powermetrics --samplers cpu_power,tasks --show-process-samp-norm --show-process-gpu -i "
-                        + freq);
+                .exec("sudo powermetrics --samplers cpu_power,tasks --show-process-samp-norm --show-process-gpu -i " + freq);
         accumulatedCPUShareDiff = 0.0;
         return new OngoingPowerMeasure(AppleSiliconMeasure.METADATA);
     }