Late-delivery deadline

Tests/Distribution/NodeFanoutSweep/Client/Program.cs

@@ -50,6 +50,11 @@ var windowSec = int.Parse(GetArg(args, "--window-sec", "60"));
 var warmupSec = int.Parse(GetArg(args, "--warmup-sec", "5"));
 var settleSec = int.Parse(GetArg(args, "--settle-sec", "5"));
 var replications = int.Parse(GetArg(args, "--replications", "3"));
+// Late-delivery deadline. The paper defines a late delivery as a gap exceeding eight emission
+// intervals (400 ms at the 50 ms default). When sweeping emit rate this MUST scale with the
+// interval, otherwise low-rate runs (e.g. 1 Hz, where deliveries are 1000 ms apart by design)
+// would flag every delivery as late. Orchestrator passes 8 x emit-interval-ms.
+var lateThresholdMs = double.Parse(GetArg(args, "--late-threshold-ms", "400"), CultureInfo.InvariantCulture);
 var nValuesStr = GetArg(args, "--n-values", "2,5,10,20,50,100,200,500");
 var outputCsv = GetArg(args, "--output", "fanout_sweep_results.csv");
 var repOutputCsv = GetArg(args, "--rep-output", "");
@@ -61,6 +66,7 @@ double minAcceptableRate = theoreticalMaxRate * 0.10;
 Console.WriteLine($"[Orchestrator] resources={resources} interval={emitIntervalMs}ms "
                 + $"window={windowSec}s replications={replications}");
 Console.WriteLine($"[Orchestrator] theoretical_max_per_subscriber_rate={theoreticalMaxRate:F0} notif/s");
+Console.WriteLine($"[Orchestrator] late_threshold={lateThresholdMs:F0} ms");
 Console.WriteLine($"[Orchestrator] saturation_threshold={minAcceptableRate:F0} notif/s");
 Console.WriteLine($"[Orchestrator] N values: {string.Join(",", nValues)}");
 
@@ -118,7 +124,7 @@ foreach (int n in nValues)
         {
             int captured = i;
             subscriberWhs[i] = new Warehouse();
-            spawnTasks[i] = SpawnSubscriber(subscriberWhs[i], host, port, resources, captured);
+            spawnTasks[i] = SpawnSubscriber(subscriberWhs[i], host, port, resources, captured, lateThresholdMs);
         }
 
         await Task.WhenAll(spawnTasks);
@@ -250,16 +256,18 @@ foreach (int n in nValues)
         Console.WriteLine($"\n[Orchestrator] N={n} SUMMARY: "
                         + $"mean_per_sub={meanOfMeans:F1} ± {ciHalfWidth:F1} notif/s (95% CI)");
 
-        // Saturation detection: stop sweep if per-sub rate falls below
+        // Saturation detection: stop sweep if per-sub rate falls below 10% of theoretical OR the
-        // 10% of theoretical OR server CPU peaked above 180% (>90% of 2 cores)
+        // server's dispatch path saturates a core. CPU is "% across all cores" (100% = one full
+        // core), and fan-out is single-threaded, so the relevant signal is a per-core plateau
+        // near 100%, not 2-core saturation.
         if (meanOfMeans < minAcceptableRate)
         {
             Console.WriteLine($"[Orchestrator] *** SATURATION DETECTED: rate {meanOfMeans:F0} < {minAcceptableRate:F0} ***");
             saturatedDetected = true;
         }
-        else if (perRepResults.Average(r => r.ServerCpuPeak) > 180.0)
+        else if (perRepResults.Average(r => r.ServerCpuPeak) > 95.0)
         {
-            Console.WriteLine($"[Orchestrator] *** SATURATION DETECTED: server CPU peaked > 180% ***");
+            Console.WriteLine($"[Orchestrator] *** SATURATION DETECTED: server dispatch core saturated (peak > 95%) ***");
             saturatedDetected = true;
         }
 
@@ -318,7 +326,7 @@ if (!string.IsNullOrWhiteSpace(repOutputCsv))
 // Subscriber spawn / teardown
 // ----------------------------------------------------------------
 static async Task<SubscriberTask?> SpawnSubscriber(
-    Warehouse wh, string host, int port, int resources, int subId)
+    Warehouse wh, string host, int port, int resources, int subId, double lateThresholdMs)
 {
     try
     {
@@ -338,7 +346,7 @@ static async Task<SubscriberTask?> SpawnSubscriber(
                 double elapsedMs = (now - lastTick) * 1000.0 / Stopwatch.Frequency;
                 lastTick = now;
                 Interlocked.Increment(ref sub._received);
-                if (elapsedMs > 400) Interlocked.Increment(ref sub._lateDeliveries);
+                if (elapsedMs > lateThresholdMs) Interlocked.Increment(ref sub._lateDeliveries);
             };
         }