Add a workaround for the tests hanging while loading MKL.

The workaround is to ensure the MKL library is loaded very early in the test process, so it doesn't cause the deadlock.

Also, undoing the previous test workarounds now that we've narrowed this hang down.

Workaround #1073

Author: eerhardt

.vsts-dotnet-ci.yml

@@ -10,7 +10,7 @@ phases:
     name: Windows_NT
     buildScript: build.cmd
     queue:
-      name: DotNetCore-Windows 
+      name: Hosted VS2017 
 
 - template: /build/ci/phase-template.yml
   parameters:

test/Microsoft.ML.Predictor.Tests/TestAutoInference.cs

@@ -27,7 +27,7 @@ public TestAutoInference(ITestOutputHelper helper)
         [TestCategory("EntryPoints")]
         public void TestLearn()
         {
-            using (var env = new LocalEnvironment()
+            using (var env = new ConsoleEnvironment()
                 .AddStandardComponents()) // AutoInference.InferPipelines uses ComponentCatalog to read text data
             {
                 string pathData = GetDataPath("adult.train");
@@ -74,7 +74,7 @@ public void TestLearn()
         [Fact(Skip = "Need CoreTLC specific baseline update")]
         public void TestTextDatasetLearn()
         {
-            using (var env = new LocalEnvironment()
+            using (var env = new ConsoleEnvironment()
                 .AddStandardComponents()) // AutoInference uses ComponentCatalog to find all learners
             {
                 string pathData = GetDataPath(@"../UnitTest/tweets_labeled_10k_test_validation.tsv");
@@ -99,7 +99,7 @@ public void TestTextDatasetLearn()
         [Fact]
         public void TestPipelineNodeCloning()
         {
-            using (var env = new LocalEnvironment()
+            using (var env = new ConsoleEnvironment()
                 .AddStandardComponents()) // RecipeInference.AllowedLearners uses ComponentCatalog to find all learners
             {
                 var lr1 = RecipeInference
@@ -142,7 +142,7 @@ public void TestHyperparameterFreezing()
             int batchSize = 1;
             int numIterations = 10;
             int numTransformLevels = 3;
-            using (var env = new LocalEnvironment()
+            using (var env = new ConsoleEnvironment()
                 .AddStandardComponents()) // AutoInference uses ComponentCatalog to find all learners
             {
                 SupportedMetric metric = PipelineSweeperSupportedMetrics.GetSupportedMetric(PipelineSweeperSupportedMetrics.Metrics.Auc);
@@ -191,7 +191,7 @@ public void TestRegressionPipelineWithMinimizingMetric()
             int batchSize = 5;
             int numIterations = 10;
             int numTransformLevels = 1;
-            using (var env = new LocalEnvironment()
+            using (var env = new ConsoleEnvironment()
                 .AddStandardComponents()) // AutoInference uses ComponentCatalog to find all learners
             {
                 SupportedMetric metric = PipelineSweeperSupportedMetrics.GetSupportedMetric(PipelineSweeperSupportedMetrics.Metrics.AccuracyMicro);
@@ -226,7 +226,7 @@ public void TestLearnerConstrainingByName()
             int numIterations = 1;
             int numTransformLevels = 2;
             var retainedLearnerNames = new[] { $"LogisticRegressionBinaryClassifier", $"FastTreeBinaryClassifier" };
-            using (var env = new LocalEnvironment()
+            using (var env = new ConsoleEnvironment()
                 .AddStandardComponents()) // AutoInference uses ComponentCatalog to find all learners
             {
                 SupportedMetric metric = PipelineSweeperSupportedMetrics.GetSupportedMetric(PipelineSweeperSupportedMetrics.Metrics.Auc);

test/Microsoft.ML.TestFramework/GlobalBase.cs

@@ -11,6 +11,7 @@
 //    }
 
 using System;
+using System.Runtime.InteropServices;
 using Xunit;
 
 namespace Microsoft.ML.Runtime.Internal.Internallearn.Test
@@ -22,6 +23,28 @@ public static void AssemblyInit()
             System.Diagnostics.Debug.WriteLine("*** Setting test assertion handler");
             var prev = Contracts.SetAssertHandler(AssertHandler);
             Contracts.Check(prev == null, "Expected to replace null assertion handler!");
+
+            // HACK: ensure MklImports is loaded very early in the tests so it doesn't deadlock while loading it later.
+            // See https://github.com/dotnet/machinelearning/issues/1073
+            Mkl.PptrfInternal(Mkl.Layout.RowMajor, Mkl.UpLo.Up, 0, Array.Empty<double>());
+        }
+
+        private static class Mkl
+        {
+            public enum Layout
+            {
+                RowMajor = 101,
+                ColMajor = 102
+            }
+
+            public enum UpLo : byte
+            {
+                Up = (byte)'U',
+                Lo = (byte)'L'
+            }
+
+            [DllImport("MklImports", EntryPoint = "LAPACKE_dpptrf")]
+            public static extern int PptrfInternal(Layout layout, UpLo uplo, int n, double[] ap);
         }
 
         public static void AssemblyCleanup()