Resource Monitoring metrics on Windows - remove multiplication by 100

src/Libraries/Microsoft.Extensions.Diagnostics.ResourceMonitoring/Windows/WindowsContainerSnapshotProvider.cs

@@ -14,7 +14,7 @@ namespace Microsoft.Extensions.Diagnostics.ResourceMonitoring.Windows;
 
 internal sealed class WindowsContainerSnapshotProvider : ISnapshotProvider
 {
-    private const double Hundred = 100.0d;
+    private const double One = 1.0d;
 
     private readonly Lazy<MEMORYSTATUSEX> _memoryStatus;
 
@@ -195,7 +195,7 @@ private double MemoryPercentage(Func<ulong> getMemoryUsage)
         {
             if (now >= _refreshAfterMemory)
             {
-                _memoryPercentage = Math.Min(Hundred, memoryUsage / _memoryLimit * Hundred); // Don't change calculation order, otherwise we loose some precision
+                _memoryPercentage = Math.Min(One, memoryUsage / _memoryLimit);
                 _refreshAfterMemory = now.Add(_memoryRefreshInterval);
             }
 
@@ -229,7 +229,7 @@ private double CpuPercentage()
                 var timeTickDelta = (now.Ticks - _oldCpuTimeTicks) * _cpuLimit;
                 if (usageTickDelta > 0 && timeTickDelta > 0)
                 {
-                    _cpuPercentage = Math.Min(Hundred, usageTickDelta / timeTickDelta * Hundred); // Don't change calculation order, otherwise precision is lost.
+                    _cpuPercentage = Math.Min(One, usageTickDelta / timeTickDelta);
 
                     Log.CpuContainerUsageData(
                         _logger, basicAccountingInfo.TotalKernelTime, basicAccountingInfo.TotalUserTime, _oldCpuUsageTicks, timeTickDelta, _cpuLimit, _cpuPercentage);

src/Libraries/Microsoft.Extensions.Diagnostics.ResourceMonitoring/Windows/WindowsSnapshotProvider.cs

@@ -14,7 +14,7 @@ namespace Microsoft.Extensions.Diagnostics.ResourceMonitoring.Windows;
 
 internal sealed class WindowsSnapshotProvider : ISnapshotProvider
 {
-    private const double Hundred = 100.0d;
+    private const double One = 1.0d;
 
     public SystemResources Resources { get; }
 
@@ -136,7 +136,7 @@ private double MemoryPercentage()
         {
             if (now >= _refreshAfterMemory)
             {
-                _memoryPercentage = Math.Min(Hundred, currentMemoryUsage / _totalMemory * Hundred); // Don't change calculation order, otherwise we loose some precision
+                _memoryPercentage = Math.Min(One, currentMemoryUsage / _totalMemory);
                 _refreshAfterMemory = now.Add(_memoryRefreshInterval);
             }
 
@@ -168,7 +168,7 @@ private double CpuPercentage()
                 var timeTickDelta = (now.Ticks - _oldCpuTimeTicks) * _cpuUnits;
                 if (usageTickDelta > 0 && timeTickDelta > 0)
                 {
-                    _cpuPercentage = Math.Min(Hundred, usageTickDelta / (double)timeTickDelta * Hundred); // Don't change calculation order, otherwise we loose some precision
+                    _cpuPercentage = Math.Min(One, usageTickDelta / (double)timeTickDelta);
 
                     Log.CpuUsageData(_logger, currentCpuTicks, _oldCpuUsageTicks, timeTickDelta, _cpuUnits, _cpuPercentage);
 

test/Libraries/Microsoft.Extensions.Diagnostics.ResourceMonitoring.Tests/Windows/WindowsContainerSnapshotProviderTests.cs

@@ -237,21 +237,21 @@ public void SnapshotProvider_EmitsCpuMetrics(string instrumentName)
         fakeClock.Advance(TimeSpan.FromMilliseconds(1));
         metricCollector.RecordObservableInstruments();
 
-        Assert.Equal(10, metricCollector.LastMeasurement.Value); // Consumed 10% of the CPU.
+        Assert.Equal(0.1, metricCollector.LastMeasurement.Value); // Consumed 10% of the CPU.
 
         // Step #2 - simulate 1 millisecond passing and collect metrics again:
         fakeClock.Advance(TimeSpan.FromMilliseconds(1));
         metricCollector.RecordObservableInstruments();
 
         // CPU usage should be the same as before, as we didn't recalculate it:
-        Assert.Equal(10, metricCollector.LastMeasurement.Value); // Still consuming 10% as gauge wasn't updated.
+        Assert.Equal(0.1, metricCollector.LastMeasurement.Value); // Still consuming 10% as gauge wasn't updated.
 
         // Step #3 - simulate 1 millisecond passing and collect metrics again:
         fakeClock.Advance(TimeSpan.FromMilliseconds(1));
         metricCollector.RecordObservableInstruments();
 
         // CPU usage should be the same as before, as we're not simulating any CPU usage:
-        Assert.Equal(10, metricCollector.LastMeasurement.Value); // Consumed 10% of the CPU.
+        Assert.Equal(0.1, metricCollector.LastMeasurement.Value); // Consumed 10% of the CPU.
     }
 
     [Theory]
@@ -294,17 +294,17 @@ public void SnapshotProvider_EmitsMemoryMetrics(string instrumentName)
         // Step #0 - state in the beginning:
         metricCollector.RecordObservableInstruments();
         Assert.NotNull(metricCollector.LastMeasurement?.Value);
-        Assert.Equal(10, metricCollector.LastMeasurement.Value); // Consuming 10% of the memory initially.
+        Assert.Equal(0.1, metricCollector.LastMeasurement.Value); // Consuming 10% of the memory initially.
 
         // Step #1 - simulate 1 millisecond passing and collect metrics again:
         fakeClock.Advance(options.MemoryConsumptionRefreshInterval - TimeSpan.FromMilliseconds(1));
         metricCollector.RecordObservableInstruments();
-        Assert.Equal(10, metricCollector.LastMeasurement.Value); // Still consuming 10% as gauge wasn't updated.
+        Assert.Equal(0.1, metricCollector.LastMeasurement.Value); // Still consuming 10% as gauge wasn't updated.
 
         // Step #2 - simulate 2 milliseconds passing and collect metrics again:
         fakeClock.Advance(TimeSpan.FromMilliseconds(1));
         metricCollector.RecordObservableInstruments();
-        Assert.Equal(30, metricCollector.LastMeasurement.Value); // Consuming 30% of the memory afterwards.
+        Assert.Equal(0.3, metricCollector.LastMeasurement.Value); // Consuming 30% of the memory afterwards.
     }
 
     [Fact]

test/Libraries/Microsoft.Extensions.Diagnostics.ResourceMonitoring.Tests/Windows/WindowsSnapshotProviderTests.cs

@@ -96,14 +96,14 @@ public void SnapshotProvider_EmitsCpuMetrics()
         // Step #1 - simulate 1 millisecond passing and collect metrics again:
         fakeClock.Advance(TimeSpan.FromMilliseconds(1));
         metricCollector.RecordObservableInstruments();
-        Assert.Equal(5, metricCollector.LastMeasurement?.Value); // Consuming 5% of the CPU (2 CPUs, 1000 ticks, 1ms).
+        Assert.Equal(0.05, metricCollector.LastMeasurement?.Value); // Consuming 5% of the CPU (2 CPUs, 1000 ticks, 1ms).
 
         // Step #2 - simulate another 1 millisecond passing and collect metrics again:
         fakeClock.Advance(TimeSpan.FromMilliseconds(1));
         metricCollector.RecordObservableInstruments();
 
         // CPU usage should be the same as before, as we're not simulating any CPU usage:
-        Assert.Equal(5, metricCollector.LastMeasurement?.Value); // Still consuming 5% of the CPU
+        Assert.Equal(0.05, metricCollector.LastMeasurement?.Value); // Still consuming 5% of the CPU
     }
 
     [ConditionalFact]
@@ -124,21 +124,21 @@ public void SnapshotProvider_EmitsMemoryMetrics()
         // Step #0 - state in the beginning:
         metricCollector.RecordObservableInstruments();
         Assert.NotNull(metricCollector.LastMeasurement);
-        Assert.Equal(10, metricCollector.LastMeasurement.Value); // Consuming 5% of the memory initially
+        Assert.Equal(0.1, metricCollector.LastMeasurement.Value); // Consuming 5% of the memory initially
 
         memoryUsed = 900L; // Simulate 30% memory usage.
 
         // Step #1 - simulate 1 millisecond passing and collect metrics again:
         fakeClock.Advance(TimeSpan.FromMilliseconds(1));
         metricCollector.RecordObservableInstruments();
 
-        Assert.Equal(10, metricCollector.LastMeasurement.Value); // Still consuming 10% as gauge wasn't updated.
+        Assert.Equal(0.1, metricCollector.LastMeasurement.Value); // Still consuming 10% as gauge wasn't updated.
 
         // Step #2 - simulate 1 millisecond passing and collect metrics again:
         fakeClock.Advance(TimeSpan.FromMilliseconds(1));
         metricCollector.RecordObservableInstruments();
 
-        Assert.Equal(30, metricCollector.LastMeasurement.Value); // Consuming 30% of the memory afterwards
+        Assert.Equal(0.3, metricCollector.LastMeasurement.Value); // Consuming 30% of the memory afterwards
 
         memoryUsed = 3_100L; // Simulate more than 100% memory usage
 
@@ -147,7 +147,7 @@ public void SnapshotProvider_EmitsMemoryMetrics()
         metricCollector.RecordObservableInstruments();
 
         // Memory usage should be the same as before, as we're not simulating any CPU usage:
-        Assert.Equal(100, metricCollector.LastMeasurement.Value); // Consuming 100% of the memory
+        Assert.Equal(1, Math.Round(metricCollector.LastMeasurement.Value)); // Consuming 100% of the memory
     }
 
     [ConditionalFact]