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‎src/PerfProblemSimulator/Properties/launchSettings.json‎

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}
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},
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"profiles": {
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"http": {
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"https": {
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"commandName": "Project",
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"dotnetRunMessages": true,
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"launchBrowser": true,
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"launchUrl": "swagger",
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"applicationUrl": "http://localhost:5221",
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"launchUrl": "",
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"applicationUrl": "https://localhost:7179;http://localhost:5221",
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"environmentVariables": {
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"ASPNETCORE_ENVIRONMENT": "Development"
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}
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},
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"https": {
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"http": {
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"commandName": "Project",
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"dotnetRunMessages": true,
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"launchBrowser": true,
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"launchUrl": "swagger",
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"applicationUrl": "https://localhost:7179;http://localhost:5221",
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"launchUrl": "",
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"applicationUrl": "http://localhost:5221",
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"environmentVariables": {
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"ASPNETCORE_ENVIRONMENT": "Development"
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}
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},
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"IIS Express": {
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"commandName": "IISExpress",
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"launchBrowser": true,
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"launchUrl": "swagger",
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"launchUrl": "",
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"environmentVariables": {
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"ASPNETCORE_ENVIRONMENT": "Development"
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}

‎src/PerfProblemSimulator/wwwroot/azure-deployment.html‎

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@@ -652,12 +652,12 @@ <h3>Assign Contributor Role</h3>
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<section id="github-secrets" class="card">
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<h2><span class="step-number">5</span> Configure GitHub Secrets</h2>
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<h3>Fork or Clone the Repository</h3>
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<h3>Clone the Repository</h3>
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<ol>
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<li><strong>Fork the Repository</strong>
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<li><strong>Clone the Repository</strong>
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<ul>
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<li>Go to the Performance Problem Simulator repository for your stack</li>
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<li>Click <strong>Fork</strong> to create your own copy</li>
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<li>Click <strong>Code</strong> and clone it to your own GitHub account</li>
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</ul>
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</li>
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</ol>

‎src/PerfProblemSimulator/wwwroot/azure-monitoring-guide.html‎

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@@ -893,12 +893,14 @@ <h4>1. Azure Auto-Heal with Slow Request Trigger</h4>
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<h4>2. CLR Profiler / Azure Profiler</h4>
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<ol>
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<li>In App Service, go to <strong>Diagnose and solve problems</strong></li>
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<li>Search for "Profiler"</li>
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<li>In the dashboard, set execution time long enough that the total simulation easily exceeds 60 seconds (e.g., 25s execution, 10s interval, 6 max requests)</li>
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<li>Click <strong>🐌 Start Slow Requests</strong> to begin the simulation</li>
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<li>Wait for the first slow request to appear in the event log — this confirms health probe rate has been reduced</li>
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<li>In App Service, go to <strong>Diagnose and solve problems</strong> → search for "Profiler"</li>
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<li>Start a <strong>CPU Profiler</strong> trace (60-120 seconds recommended)</li>
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<li>Trigger the slow request simulation</li>
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<li>Download and analyze the trace</li>
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<li>Wait for the trace to complete, then download and analyze</li>
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</ol>
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<p><strong>Why start the simulation first?</strong> The app automatically slows health probes while slow request simulations are active. Starting the simulation before the profiler keeps health probe noise out of the trace, giving you a cleaner profile focused on the blocking patterns.</p>
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<h3>What to Look For in CLR Profiler</h3>
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<p>The service uses three different sync-over-async patterns with <strong>intentionally descriptive method names</strong>:</p>
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</div>
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</section>
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<!-- Using the Request Latency Monitor Section -->
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<section id="latency" class="doc-section">
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<h2>⏱️ Using the Request Latency Monitor</h2>
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<p>The dashboard includes a <strong>Request Latency Monitor</strong> that demonstrates how thread pool starvation affects request processing time.</p>
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<h3>How It Works</h3>
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<ol>
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<li>A dedicated background thread (not from the thread pool) continuously sends probe requests to <code>/api/health/probe</code></li>
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<li>The probe endpoint is lightweight - it simply returns a timestamp</li>
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<li>Latency is measured from request start to response received</li>
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<li>Results are broadcast via SignalR to the dashboard</li>
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</ol>
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<h3>What to Observe</h3>
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<table class="latency-table">
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<thead>
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<tr>
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<th>Scenario</th>
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<th>Latency (Total)</th>
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<th>Status</th>
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<th>What's Happening</th>
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</tr>
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</thead>
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<tbody>
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<tr>
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<td>Normal operation</td>
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<td>&lt; 150ms</td>
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<td>✅ Good</td>
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<td>Thread pool threads are available</td>
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</tr>
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<tr>
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<td>Mild starvation</td>
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<td>150ms - 1s</td>
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<td>⚠️ Degraded</td>
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<td>Requests queued waiting for threads</td>
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</tr>
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<tr>
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<td>Severe starvation</td>
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<td>&gt; 1s</td>
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<td>❌ Severe</td>
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<td>Significant queuing delay</td>
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</tr>
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<tr>
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<td>Timeout</td>
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<td>30s</td>
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<td>❌ Critical</td>
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<td>No thread available within timeout</td>
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</tr>
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</tbody>
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</table>
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<div class="info-box">
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<h4>Key Insight</h4>
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<p>The probe runs on a <strong>dedicated thread</strong> (not from the thread pool), so it can always send requests. However, the ASP.NET Core server uses the thread pool to process incoming requests. During starvation:</p>
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<ol>
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<li>The probe request is sent immediately</li>
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<li>The request sits in the ASP.NET Core queue</li>
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<li>It waits for a thread pool thread to become available</li>
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<li>Latency = time spent waiting + processing time</li>
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</ol>
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<p>This directly demonstrates how sync-over-async anti-patterns impact end-user response times.</p>
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</div>
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<h3>Correlating with Azure Metrics</h3>
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<p>Compare the dashboard's latency chart with:</p>
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<ul>
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<li><strong>Application Insights</strong> &gt; Live Metrics &gt; Request Duration</li>
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<li><strong>App Service Metrics</strong> &gt; Response Time</li>
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<li><strong>Thread Pool</strong> section showing blocked threads</li>
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</ul>
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</section>
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<!-- Recommended Monitoring Setup Section -->
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<section id="setup" class="doc-section">
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<h2>🛠️ Recommended Monitoring Setup</h2>
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<h3>1. Enable Application Insights</h3>
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<div class="code-block">
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<span class="comment"># Via Azure CLI</span>
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az monitor app-insights component create \
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--app ai-perf-simulator \
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--location eastus \
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--resource-group rg-perf-simulator \
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--application-type web
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<span class="comment"># Get instrumentation key</span>
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az monitor app-insights component show \
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--app ai-perf-simulator \
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--resource-group rg-perf-simulator \
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--query instrumentationKey -o tsv
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</div>
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<h3>2. Configure Alerts</h3>
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<p>Create alerts for:</p>
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<table class="alert-table">
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<thead>
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<tr>
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<th>Metric</th>
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<th>Threshold</th>
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<th>Action</th>
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</thead>
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<tbody>
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<td>CPU Percentage</td>
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<td>&gt; 80% for 5 min</td>
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<td>Email</td>
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</tr>
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<tr>
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<td>Memory Working Set</td>
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<td>&gt; 1 GB</td>
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<td>Email</td>
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</tr>
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<tr>
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<td>Response Time</td>
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<td>&gt; 5s average</td>
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<td>Email</td>
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</tr>
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<tr>
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<td>Failed Requests</td>
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<td>&gt; 10/minute</td>
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<td>Email + PagerDuty</td>
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</tr>
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</tbody>
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</table>
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<h3>3. Enable Diagnostic Logs</h3>
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<div class="code-block">
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az webapp log config \
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--resource-group rg-perf-simulator \
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--name your-app-name \
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--application-logging filesystem \
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--detailed-error-messages <span class="keyword">true</span> \
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--failed-request-tracing <span class="keyword">true</span> \
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--web-server-logging filesystem
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</div>
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</section>
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<!-- Best Practices Section -->
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<section id="best-practices" class="doc-section">
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<h2>📈 Best Practices</h2>
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<div class="best-practices">
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<div class="do-list">
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<h4>DO:</h4>
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<ul>
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<li>Use Application Insights for production apps</li>
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<li>Set up alerts before issues occur</li>
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<li>Enable diagnostic logging proactively</li>
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<li>Monitor thread pool metrics</li>
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<li>Use async/await properly throughout</li>
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</ul>
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</div>
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<div class="dont-list">
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<h4>DON'T:</h4>
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<ul>
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<li>Use <code>.Wait()</code> or <code>.Result</code> on async methods</li>
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<li>Block thread pool threads</li>
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<li>Allocate large pinned arrays without releasing</li>
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<li>Use spin loops for delays</li>
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<li>Ignore memory growth over time</li>
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</ul>
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</div>
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</div>
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</section>
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<!-- Additional Resources Section -->
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<section id="resources" class="doc-section">
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<h2>🔗 Additional Resources</h2>
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<a href="#failedrequests"><span class="toc-icon">❌</span>Failed Requests</a>
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</li>
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<li class="doc-toc-divider-item" aria-hidden="true"></li>
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<li class="doc-toc-section-item">Tools</li>
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<li class="doc-toc-item">
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<a href="#latency"><span class="toc-icon">⏱️</span>Latency Monitor</a>
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</li>
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<li class="doc-toc-divider-item" aria-hidden="true"></li>
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<li class="doc-toc-section-item">Reference</li>
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<a href="#setup"><span class="toc-icon">⚙️</span>Setup</a>
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</li>
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<li class="doc-toc-item">
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<a href="#best-practices"><span class="toc-icon">✅</span>Best Practices</a>
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</li>
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<li class="doc-toc-item">
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<a href="#resources"><span class="toc-icon">📚</span>Resources</a>
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‎src/PerfProblemSimulator/wwwroot/css/dashboard.css‎

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}
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.indicator.connected {
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background: var(--color-success);
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box-shadow: 0 0 8px var(--color-success);
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background: #2ecc40;
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box-shadow: 0 0 8px #2ecc40;
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}
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.indicator.disconnected {
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padding: 0.625rem 1.25rem;
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border-radius: 50%;
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cursor: pointer;
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font-size: 1rem;

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