CPU simulation simplification update

rhamlett · rhamlett · commit 95aaa2e2d525 · 2026-02-23T13:35:32.000-05:00
diff --git a/src/PerfProblemSimulator/Controllers/CpuController.cs b/src/PerfProblemSimulator/Controllers/CpuController.cs
@@ -103,24 +103,24 @@ public async Task<IActionResult> TriggerHighCpu(
     {
         // Use defaults if no request body provided
         var durationSeconds = request?.DurationSeconds ?? 30;
-        var targetPercentage = request?.TargetPercentage ?? 100;
+        var level = request?.Level ?? "high";
 
         // Log the incoming request (FR-010: Request logging)
         _logger.LogInformation(
-            "Received CPU stress request: DurationSeconds={Duration}, Percentage={Percentage}, ClientIP={ClientIP}",
+            "Received CPU stress request: DurationSeconds={Duration}, Level={Level}, ClientIP={ClientIP}",
             durationSeconds,
-            targetPercentage,
+            level,
             HttpContext.Connection.RemoteIpAddress);
 
         try
         {
-            var result = await _cpuStressService.TriggerCpuStressAsync(durationSeconds, cancellationToken, targetPercentage);
+            var result = await _cpuStressService.TriggerCpuStressAsync(durationSeconds, cancellationToken, level);
 
             _logger.LogInformation(
-                "Started CPU stress simulation {SimulationId} for {Duration}s @ {Percentage}%",
+                "Started CPU stress simulation {SimulationId} for {Duration}s @ {Level}",
                 result.SimulationId,
                 result.ActualParameters?["DurationSeconds"],
-                result.ActualParameters?["TargetPercentage"]);
+                result.ActualParameters?["Level"]);
 
             return Ok(result);
         }
diff --git a/src/PerfProblemSimulator/Models/CpuStressRequest.cs b/src/PerfProblemSimulator/Models/CpuStressRequest.cs
@@ -28,23 +28,19 @@ public class CpuStressRequest
     /// Default: 30 seconds. This is enough time to observe CPU metrics spike
     /// in monitoring tools like Task Manager, dotnet-counters, or Application Insights.
     /// </para>
-    /// <para>
-    /// Values exceeding the configured maximum (default: 300 seconds) will be
-    /// automatically capped to prevent runaway CPU consumption.
-    /// </para>
     /// </remarks>
     [Range(1, int.MaxValue, ErrorMessage = "Duration must be at least 1 second")]
     public int DurationSeconds { get; set; } = 30;
 
     /// <summary>
-    /// The target CPU usage percentage (1-100).
+    /// The intensity level: "moderate" (~65% CPU) or "high" (~100% CPU).
     /// </summary>
     /// <remarks>
     /// <para>
-    /// Default: 100%. Lower values use a duty cycle (work/sleep) to simulate
-    /// partial CPU load.
+    /// Default: "high". 
+    /// - Moderate: Uses duty cycling to target approximately 65% CPU usage
+    /// - High: Full spin loops for maximum CPU consumption
     /// </para>
     /// </remarks>
-    [Range(1, 100, ErrorMessage = "Target percentage must be between 1 and 100")]
-    public int TargetPercentage { get; set; } = 100;
+    public string Level { get; set; } = "high";
 }
diff --git a/src/PerfProblemSimulator/Services/CpuStressService.cs b/src/PerfProblemSimulator/Services/CpuStressService.cs
@@ -84,7 +84,7 @@ public CpuStressService(
     }
 
     /// <inheritdoc />
-    public Task<SimulationResult> TriggerCpuStressAsync(int durationSeconds, CancellationToken cancellationToken, int targetPercentage = 100)
+    public Task<SimulationResult> TriggerCpuStressAsync(int durationSeconds, CancellationToken cancellationToken, string level = "high")
     {
         // ==========================================================================
         // STEP 1: Validate the duration (no upper limits - app is meant to break)
@@ -93,7 +93,12 @@ public Task<SimulationResult> TriggerCpuStressAsync(int durationSeconds, Cancell
             ? DefaultDurationSeconds
             : durationSeconds;
 
-        var actualPercentage = Math.Clamp(targetPercentage, 1, 100);
+        // Normalize level to lowercase and default to "high" if invalid
+        var normalizedLevel = (level?.ToLowerInvariant()) switch
+        {
+            "moderate" => "moderate",
+            _ => "high"
+        };
 
         var simulationId = Guid.NewGuid();
         var startedAt = DateTimeOffset.UtcNow;
@@ -111,17 +116,17 @@ public Task<SimulationResult> TriggerCpuStressAsync(int durationSeconds, Cancell
         {
             ["DurationSeconds"] = actualDuration,
             ["ProcessorCount"] = processorCount,
-            ["TargetPercentage"] = actualPercentage
+            ["Level"] = normalizedLevel
         };
 
         // Register this simulation with the tracker
         _simulationTracker.RegisterSimulation(simulationId, SimulationType.Cpu, parameters, cts);
 
         _logger.LogInformation(
-            "Starting CPU stress simulation {SimulationId}: {Duration}s @ {Percentage}% across {ProcessorCount} cores",
+            "Starting CPU stress simulation {SimulationId}: {Duration}s @ {Level} across {ProcessorCount} cores",
             simulationId,
             actualDuration,
-            actualPercentage,
+            normalizedLevel,
             processorCount);
 
         // ==========================================================================
@@ -132,7 +137,7 @@ public Task<SimulationResult> TriggerCpuStressAsync(int durationSeconds, Cancell
         // This is important because the caller (HTTP request) shouldn't be blocked
         // waiting for the entire duration.
 
-        _ = Task.Run(() => ExecuteCpuStress(simulationId, actualDuration, actualPercentage, cts.Token), cts.Token);
+        _ = Task.Run(() => ExecuteCpuStress(simulationId, actualDuration, normalizedLevel, cts.Token), cts.Token);
 
         // ==========================================================================
         // STEP 4: Return the result immediately
@@ -145,7 +150,7 @@ public Task<SimulationResult> TriggerCpuStressAsync(int durationSeconds, Cancell
             SimulationId = simulationId,
             Type = SimulationType.Cpu,
             Status = "Started",
-            Message = $"CPU stress started on {processorCount} cores for {actualDuration} seconds at {actualPercentage}%. " +
+            Message = $"CPU stress started on {processorCount} cores for {actualDuration} seconds ({normalizedLevel} intensity). " +
                       "Observe CPU metrics in Task Manager, dotnet-counters, or Application Insights. " +
                       "High CPU like this is typically caused by spin loops, inefficient algorithms, or infinite loops.",
             ActualParameters = parameters,
@@ -165,8 +170,8 @@ public Task<SimulationResult> TriggerCpuStressAsync(int durationSeconds, Cancell
     /// </para>
     /// <para>
     /// This method uses dedicated threads with spin loops to consume available CPU.
-    /// If targetPercentage is 100, it runs a tight loop.
-    /// If targetPercentage is less than 100, it uses a duty cycle (work/sleep) to simulate load.
+    /// For "high" level, it runs a tight loop for ~100% usage.
+    /// For "moderate" level, it uses a duty cycle (work/sleep) to simulate ~65% load.
     /// </para>
     /// <para>
     /// <strong>Why Dedicated Threads Instead of Parallel.For?</strong>
@@ -175,8 +180,11 @@ public Task<SimulationResult> TriggerCpuStressAsync(int durationSeconds, Cancell
     /// thread pool remains available for the dashboard and metrics collection.
     /// </para>
     /// </remarks>
-    private void ExecuteCpuStress(Guid simulationId, int durationSeconds, int targetPercentage, CancellationToken cancellationToken)
+    private void ExecuteCpuStress(Guid simulationId, int durationSeconds, string level, CancellationToken cancellationToken)
     {
+        // Convert level to internal percentage: moderate = 65%, high = 100%
+        var targetPercentage = level == "moderate" ? 65 : 100;
+        
         try
         {
             // Calculate the end time using Stopwatch for high precision
diff --git a/src/PerfProblemSimulator/Services/ICpuStressService.cs b/src/PerfProblemSimulator/Services/ICpuStressService.cs
@@ -26,8 +26,8 @@ public interface ICpuStressService
     /// <param name="cancellationToken">
     /// Token to request early cancellation of the stress operation.
     /// </param>
-    /// <param name="targetPercentage">
-    /// Target CPU usage percentage (1-100). Default is 100.
+    /// <param name="level">
+    /// Intensity level: "moderate" (~65% CPU) or "high" (~100% CPU). Default is "high".
     /// </param>
     /// <returns>
     /// A result containing the simulation ID, actual parameters used, and timing information.
@@ -43,8 +43,9 @@ public interface ICpuStressService
     /// <list type="bullet">
     /// <item><term>DurationSeconds</term><description>Actual duration used (may be capped)</description></item>
     /// <item><term>ProcessorCount</term><description>Number of cores being stressed</description></item>
+    /// <item><term>Level</term><description>The intensity level used</description></item>
     /// </list>
     /// </para>
     /// </remarks>
-    Task<SimulationResult> TriggerCpuStressAsync(int durationSeconds, CancellationToken cancellationToken, int targetPercentage = 100);
+    Task<SimulationResult> TriggerCpuStressAsync(int durationSeconds, CancellationToken cancellationToken, string level = "high");
 }
diff --git a/src/PerfProblemSimulator/wwwroot/css/dashboard.css b/src/PerfProblemSimulator/wwwroot/css/dashboard.css
@@ -553,31 +553,100 @@ body {
 }
 
 .btn-danger {
-    background: var(--color-danger);
+    background: linear-gradient(135deg, #8b0000 0%, #4a0000 100%);
     color: white;
+    border: 2px solid #ff0000;
+    animation: pulse-danger 2s infinite;
 }
 
 .btn-danger:hover:not(:disabled) {
-    background: #a52a2d;
+    background: linear-gradient(135deg, #a00000 0%, #600000 100%);
+    border-color: #ff4444;
+}
+
+@keyframes pulse-danger {
+    0%, 100% { box-shadow: 0 0 5px rgba(255, 0, 0, 0.3); }
+    50% { box-shadow: 0 0 15px rgba(255, 0, 0, 0.6); }
+}
+
+/* --------------------------------------------------------------------------
+   Button Groups & Trigger Buttons (PHP-style)
+   -------------------------------------------------------------------------- */
+.btn-group {
+    display: flex;
+    gap: 0.5rem;
+    margin-top: 0.5rem;
+}
+
+.btn-trigger {
+    color: white;
+    flex: 1;
+    font-size: 0.8rem;
+    padding: 0.5rem 0.75rem;
+}
+
+.btn-cpu {
+    background: var(--color-cpu);
+}
+
+.btn-cpu:hover:not(:disabled) {
+    background: var(--color-primary-dark);
+}
+
+.btn-memory {
+    background: var(--color-success);
+    flex: 1;
+}
+
+.btn-memory:hover:not(:disabled) {
+    background: #0b5e0b;
+}
+
+.btn-release {
+    background: var(--color-secondary);
+    color: white;
+    flex: 1;
+}
+
+.btn-release:hover:not(:disabled) {
+    background: #5a6268;
+}
+
+.btn-threadblock {
+    background: var(--color-threads);
+}
+
+.btn-threadblock:hover:not(:disabled) {
+    background: #5c2d91;
+}
+
+.btn-stop {
+    background: #d13438 !important;
+    color: white !important;
+    padding: 0.5rem 0.75rem;
+    font-size: 0.8rem;
+    flex: 0 0 auto;
+    border: none;
+    box-shadow: 0 0 0 3px white;
+}
+
+.btn-stop:hover:not(:disabled) {
+    background: #a52a2d !important;
 }
 
 .btn-crash {
     background: linear-gradient(135deg, #8b0000 0%, #4a0000 100%);
     color: white;
     border: 2px solid #ff0000;
     animation: pulse-danger 2s infinite;
+    width: 100%;
 }
 
 .btn-crash:hover:not(:disabled) {
     background: linear-gradient(135deg, #a00000 0%, #600000 100%);
     border-color: #ff4444;
 }
 
-@keyframes pulse-danger {
-    0%, 100% { box-shadow: 0 0 5px rgba(255, 0, 0, 0.3); }
-    50% { box-shadow: 0 0 15px rgba(255, 0, 0, 0.6); }
-}
-
 .cpu-group {
     border: 2px solid rgba(0, 120, 212, 0.3);
     background: rgba(0, 120, 212, 0.05);
@@ -611,6 +680,7 @@ body {
     color: white;
     border: 2px solid #ffa500;
     animation: pulse-slow 3s infinite;
+    flex: 1;
 }
 
 .btn-slowrequest:hover:not(:disabled) {
diff --git a/src/PerfProblemSimulator/wwwroot/index.html b/src/PerfProblemSimulator/wwwroot/index.html
@@ -86,19 +86,19 @@ <h3>🔥 CPU Stress</h3>
                 <p>Creates parallel spin loops to max out all CPU cores.</p>
                 <div class="control-inputs">
                     <label>Duration (s):
-                        <input type="number" id="cpuDuration" value="10" min="1" title="Duration in seconds (minimum 1 second)">
+                        <input type="number" id="cpuDuration" value="30" min="1" title="Duration in seconds (minimum 1 second)">
                     </label>
-                    <label>Target Load:
-                        <select id="cpuTarget" title="Target CPU load range" class="wide-input">
-                            <option value="55">50% - 60%</option>
-                            <option value="65">60% - 70%</option>
-                            <option value="75" selected>70% - 80%</option>
-                            <option value="90">80% - 90%</option>
-                            <option value="100">90% - 100%</option>
+                    <label>Intensity:
+                        <select id="cpuLevel" class="wide-input">
+                            <option value="moderate">Moderate</option>
+                            <option value="high" selected>High</option>
                         </select>
                     </label>
                 </div>
-                <button class="btn btn-danger" id="btnTriggerCpu">🔥 Trigger High CPU</button>
+                <div class="btn-group">
+                    <button class="btn btn-trigger btn-cpu" id="btnTriggerCpu">🔥 Trigger CPU Stress</button>
+                    <button class="btn btn-stop" id="btnStopCpu">⬛ Stop</button>
+                </div>
             </div>
 
             <div class="control-group memory-group">
@@ -109,8 +109,10 @@ <h3>📊 Memory Pressure</h3>
                         <input type="number" id="memorySize" value="512" min="1" title="Memory size in megabytes (minimum 1 MB). Allocations are cumulative until released.">
                     </label>
                 </div>
-                <button class="btn btn-warning" id="btnAllocateMemory">📊 Allocate</button>
-                <button class="btn btn-secondary" id="btnReleaseMemory">🗑️ Release</button>
+                <div class="btn-group">
+                    <button class="btn btn-trigger btn-memory" id="btnAllocateMemory">📈 Allocate</button>
+                    <button class="btn btn-trigger btn-release" id="btnReleaseMemory">🗑️ Release</button>
+                </div>
             </div>
 
             <div class="control-group thread-group">
@@ -124,7 +126,9 @@ <h3>🧵 Thread Pool Starvation</h3>
                         <input type="number" id="threadConcurrent" value="100" min="1" title="Number of concurrent blocking operations (minimum 1)">
                     </label>
                 </div>
-                <button class="btn btn-danger" id="btnTriggerThreadBlock">🧵 Block Threads</button>
+                <div class="btn-group">
+                    <button class="btn btn-trigger btn-threadblock" id="btnTriggerThreadBlock">🧵 Block Threads</button>
+                </div>
             </div>
 
             <div class="control-group slowrequest-group">
@@ -142,8 +146,10 @@ <h3>🐌 Slow Requests</h3>
                         <input type="number" id="slowRequestMax" value="10" min="1" max="100" title="Total requests to generate">
                     </label>
                 </div>
-                <button class="btn btn-slowrequest" id="btnStartSlowRequests">🐌 Start Slow Requests</button>
-                <button class="btn btn-secondary" id="btnStopSlowRequests">⏹️ Stop</button>
+                <div class="btn-group">
+                    <button class="btn btn-trigger btn-slowrequest" id="btnStartSlowRequests">🐌 Start Slow Requests</button>
+                    <button class="btn btn-stop" id="btnStopSlowRequests">⬛ Stop</button>
+                </div>
             </div>
 
             <div class="control-group crash-group">
@@ -159,13 +165,10 @@ <h3>💥 Application Crash</h3>
                             <option value="OutOfMemory">Out of Memory</option>
                         </select>
                     </label>
-                    <!-- Delay option commented out - not serving a useful purpose
-                    <label>Delay (s):
-                        <input type="number" id="crashDelay" value="0" min="0" title="Optional delay before crash (0 = immediate)">
-                    </label>
-                    -->
                 </div>
-                <button class="btn btn-crash" id="btnTriggerCrash">💀 Trigger Crash</button>
+                <div class="btn-group">
+                    <button class="btn btn-trigger btn-danger" id="btnTriggerCrash">💥 Trigger Crash</button>
+                </div>
                 <p class="crash-warning">⚠️ This will TERMINATE the app!</p>
             </div>
         </div>
diff --git a/src/PerfProblemSimulator/wwwroot/js/dashboard.js b/src/PerfProblemSimulator/wwwroot/js/dashboard.js
