[Infra] trialling memory management tweaks for linux on test steps (#28557)

Author: DanielMicrosoft

.azure-pipelines/PipelineSteps/test-steps.ps1

@@ -31,7 +31,19 @@ if ($PowerShellPlatform) {
 $preference = $ErrorActionPreference
 $ErrorActionPreference = 'Continue'
 $buildProjPath = Join-Path $RepoRoot 'build.proj'
-dotnet msbuild $buildProjPath /t:Test "/p:Configuration=$Configuration;TestFramework=$TestFramework"
+
+$buildArgs = "/p:Configuration=$Configuration;TestFramework=$TestFramework"
+
+if ($IsLinux) {
+    # Applying various parallelism/heap restriction behaviors to prevent OOM issues on Ubuntu 24.04
+    Write-Host -ForegroundColor Yellow "Detected Linux agent – applying memory tuning for tests"
+    $env:DOTNET_gcServer = "0"
+    $env:DOTNET_gcHeapCount = "2"
+    $buildArgs += ";RunConfiguration.MaxCpuCount=2"
+}
+
+dotnet msbuild $buildProjPath /t:Test $buildArgs
+
 Write-Host -ForegroundColor DarkGreen "-------------------- End testing ... --------------------`n`n`n`n`n"
 
 # Test AutoGen Modules With PowerShell Core