[Perf] Display results with 4 significant figures

common/perf-test-core/src/main/java/com/azure/perf/test/core/NumberFormatter.java

@@ -0,0 +1,38 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+package com.azure.perf.test.core;
+
+import java.lang.Math;
+
+public final class NumberFormatter {
+    private NumberFormatter() { }
+
+    // Formats a number with a minimum number of significant digits.
+    // Digits to the left of the decimal point are always significant.
+    // Examples:
+    // - Format(0, 4) -> "0.000"
+    // - Format(12345, 4) -> "12,345"
+    // - Format(1.2345, 4) -> "1.235"
+    // - Format(0.00012345, 4) -> "0.0001235"
+    public static String Format(double value, int minSignificantDigits) {
+        if (minSignificantDigits < 0) {
+            throw new IllegalArgumentException("minSignificantDigits must be greater than zero");
+        }
+
+        // Special case since log(0) is undefined
+        if (value == 0) {
+            return String.format("%." + (minSignificantDigits - 1) + "f", value);
+        }
+
+        double log = Math.log10(Math.abs(value));
+        int significantDigits = (int)Math.max(Math.ceil(log), minSignificantDigits);
+
+        double divisor = Math.pow(10, Math.ceil(log) - significantDigits);
+        double rounded = divisor * Math.round(value / divisor);
+
+        int decimals = (int)Math.max(0, significantDigits - Math.floor(log) - 1);
+
+        return String.format("%,." + decimals + "f", rounded);
+    }
+}

common/perf-test-core/src/main/java/com/azure/perf/test/core/PerfStressProgram.java

@@ -278,8 +278,11 @@ public static void runTests(PerfTestBase<?>[] tests, boolean sync, int parallel,
         double secondsPerOperation = 1 / operationsPerSecond;
         double weightedAverageSeconds = totalOperations / operationsPerSecond;
 
-        System.out.printf("Completed %,d operations in a weighted-average of %,.2fs (%,.2f ops/s, %,.3f s/op)%n",
-            totalOperations, weightedAverageSeconds, operationsPerSecond, secondsPerOperation);
+        System.out.printf("Completed %,d operations in a weighted-average of %ss (%s ops/s, %s s/op)%n",
+            totalOperations,
+            NumberFormatter.Format(weightedAverageSeconds, 4),
+            NumberFormatter.Format(operationsPerSecond, 4),
+            NumberFormatter.Format(secondsPerOperation, 4));
         System.out.println();
     }