[SYSTEMDS-3730] Add time measurement

This commit adds logs to measure the speedup between the single threaded and multithreaded roll operation (on dense and sparse matrices).

Author: Biranavan Parameswaran

src/test/java/org/apache/sysds/test/component/matrix/libMatrixReorg/RollOperationThreadSafetyTest.java

@@ -28,6 +28,7 @@
 import org.apache.sysds.runtime.matrix.data.MatrixBlock;
 import org.apache.sysds.runtime.matrix.operators.ReorgOperator;
 import org.apache.sysds.test.TestUtils;
+import org.apache.sysds.utils.stats.Timing;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.junit.runners.Parameterized;
@@ -88,8 +89,17 @@ public static Collection<Object[]> data() {
 	public void denseRollOperationSingleAndMultiThreadedShouldReturnSameResult() {
 		int numThreads = getNumThreads();
 
+		// Single-threaded timing
+		Timing tSingle = new Timing(true);
 		MatrixBlock outSingle = rollOperation(inputDense, 1);
+		double timeSingle = tSingle.stop();
+
+		// Multithreaded timing
+		Timing tMulti = new Timing(true);
 		MatrixBlock outMulti = rollOperation(inputDense, numThreads);
+		double timeMulti = tMulti.stop();
+
+		logTiming("Dense", numThreads, timeSingle, timeMulti);
 
 		TestUtils.compareMatrices(outSingle, outMulti, 1e-12,
 			"Dense Mismatch (numThreads=1 vs numThreads>1) for Size=" + rows + "x" + cols + " Shift=" + shift);
@@ -99,8 +109,17 @@ public void denseRollOperationSingleAndMultiThreadedShouldReturnSameResult() {
 	public void sparseRollOperationSingleAndMultiThreadedShouldReturnSameResult() {
 		int numThreads = getNumThreads();
 
+		// Single-threaded timing
+		Timing tSingle = new Timing(true);
 		MatrixBlock outSingle = rollOperation(inputSparse, 1);
+		double timeSingle = tSingle.stop();
+
+		// Multithreaded timing
+		Timing tMulti = new Timing(true);
 		MatrixBlock outMulti = rollOperation(inputSparse, numThreads);
+		double timeMulti = tMulti.stop();
+
+		logTiming("Sparse", numThreads, timeSingle, timeMulti);
 
 		TestUtils.compareMatrices(outSingle, outMulti, 1e-12,
 			"Sparse Mismatch (numThreads=1 vs numThreads>1) for Size=" + rows + "x" + cols + " Shift=" + shift);
@@ -120,4 +139,14 @@ private static int getNumThreads() {
 		int cores = Runtime.getRuntime().availableProcessors();
 		return Math.max(2, cores);
 	}
+
+	private void logTiming(String type, int numThreads, double timeSingle, double timeMulti) {
+		double speedup = timeSingle / timeMulti;
+
+		System.out.println("\n--- " + type + " Roll Operation Timing for " + rows + "x" + cols + ", Shift=" + shift + " ---");
+		System.out.printf("Single-threaded (1 core) took: %.3f ms\n", timeSingle);
+		System.out.printf("Multithreaded (%d cores) took: %.3f ms\n", numThreads, timeMulti);
+		System.out.printf("Speedup: %.2f\n", speedup);
+		System.out.println("--------------------------------------------------------------------------------");
+	}
 }