diff --git a/build/Common.props b/build/Common.props
index 8b8f3c000..b5496a87e 100644
--- a/build/Common.props
+++ b/build/Common.props
@@ -41,7 +41,7 @@
     <StackExchangeRedisPkgVer>[2.1.58,3.0)</StackExchangeRedisPkgVer>
     <StyleCopAnalyzersPkgVer>[1.1.118,2.0)</StyleCopAnalyzersPkgVer>
     <SystemCollectionsImmutablePkgVer>1.4.0</SystemCollectionsImmutablePkgVer>
-    <SystemDiagnosticSourcePkgVer>6.0.0-preview.6.21352.12</SystemDiagnosticSourcePkgVer>
+    <SystemDiagnosticSourcePkgVer>6.0.0-rc.1.21451.13</SystemDiagnosticSourcePkgVer>
     <SystemReflectionEmitLightweightPkgVer>4.7.0</SystemReflectionEmitLightweightPkgVer>
     <SystemTextJsonPkgVer>4.7.0</SystemTextJsonPkgVer>
     <SystemThreadingTasksExtensionsPkgVer>4.5.3</SystemThreadingTasksExtensionsPkgVer>
diff --git a/src/OpenTelemetry.Api/CHANGELOG.md b/src/OpenTelemetry.Api/CHANGELOG.md
index e595a1cf2..6ae346519 100644
--- a/src/OpenTelemetry.Api/CHANGELOG.md
+++ b/src/OpenTelemetry.Api/CHANGELOG.md
@@ -2,6 +2,8 @@
 
 ## Unreleased
 
+* Updated System.Diagnostics.DiagnosticSource to version 6.0.0-rc.1.21451.13
+
 ## 1.2.0-alpha3
 
 Released 2021-Sep-13
diff --git a/src/OpenTelemetry/Metrics/AggregatorStore.cs b/src/OpenTelemetry/Metrics/AggregatorStore.cs
index 1968ef0e7..ada0440f4 100644
--- a/src/OpenTelemetry/Metrics/AggregatorStore.cs
+++ b/src/OpenTelemetry/Metrics/AggregatorStore.cs
@@ -115,8 +115,7 @@ namespace OpenTelemetry.Metrics
                     // check again after acquiring lock.
                     if (!value2metrics.TryGetValue(tagValue, out aggregatorIndex))
                     {
-                        Interlocked.Increment(ref this.metricPointIndex);
-                        aggregatorIndex = this.metricPointIndex;
+                        aggregatorIndex = Interlocked.Increment(ref this.metricPointIndex);
                         if (aggregatorIndex >= MaxMetricPoints)
                         {
                             // sorry! out of data points.
diff --git a/test/Benchmarks/Metrics/MetricsBenchmarks.cs b/test/Benchmarks/Metrics/MetricsBenchmarks.cs
index dcf2695dc..3a45c444d 100644
--- a/test/Benchmarks/Metrics/MetricsBenchmarks.cs
+++ b/test/Benchmarks/Metrics/MetricsBenchmarks.cs
@@ -29,16 +29,20 @@ Intel Core i7-8650U CPU 1.90GHz (Kaby Lake R), 1 CPU, 8 logical and 4 physical c
   DefaultJob : .NET Core 3.1.17 (CoreCLR 4.700.21.31506, CoreFX 4.700.21.31502), X64 RyuJIT
 
 
-|                    Method | WithSDK |      Mean |     Error |     StdDev |    Median |  Gen 0 | Gen 1 | Gen 2 | Allocated |
-|-------------------------- |-------- |----------:|----------:|-----------:|----------:|-------:|------:|------:|----------:|
-|            CounterHotPath |   False |  18.48 ns |  0.366 ns |   0.570 ns |  18.52 ns |      - |     - |     - |         - |
-| CounterWith1LabelsHotPath |   False |  30.25 ns |  1.274 ns |   3.530 ns |  29.14 ns |      - |     - |     - |         - |
-| CounterWith3LabelsHotPath |   False |  82.93 ns |  2.586 ns |   7.124 ns |  81.79 ns |      - |     - |     - |         - |
-| CounterWith5LabelsHotPath |   False | 134.94 ns |  4.756 ns |  13.491 ns | 132.45 ns | 0.0248 |     - |     - |     104 B |
-|            CounterHotPath |    True |  68.58 ns |  1.417 ns |   3.228 ns |  68.40 ns |      - |     - |     - |         - |
-| CounterWith1LabelsHotPath |    True | 192.19 ns |  8.114 ns |  23.151 ns | 184.06 ns |      - |     - |     - |         - |
-| CounterWith3LabelsHotPath |    True | 799.33 ns | 47.442 ns | 136.882 ns | 757.73 ns |      - |     - |     - |         - |
-| CounterWith5LabelsHotPath |    True | 972.16 ns | 45.809 ns | 133.626 ns | 939.95 ns | 0.0553 |     - |     - |     232 B |
+|                    Method | WithSDK |        Mean |     Error |    StdDev |      Median |  Gen 0 | Gen 1 | Gen 2 | Allocated |
+|-------------------------- |-------- |------------:|----------:|----------:|------------:|-------:|------:|------:|----------:|
+|            CounterHotPath |   False |    21.16 ns |  1.807 ns |  5.037 ns |    19.55 ns |      - |     - |     - |         - |
+| CounterWith1LabelsHotPath |   False |    32.33 ns |  1.596 ns |  4.501 ns |    30.53 ns |      - |     - |     - |         - |
+| CounterWith3LabelsHotPath |   False |    88.70 ns |  3.963 ns | 11.497 ns |    86.24 ns |      - |     - |     - |         - |
+| CounterWith5LabelsHotPath |   False |   122.19 ns |  4.101 ns | 11.898 ns |   120.32 ns | 0.0248 |     - |     - |     104 B |
+| CounterWith6LabelsHotPath |   False |   151.19 ns |  5.875 ns | 17.324 ns |   146.80 ns | 0.0286 |     - |     - |     120 B |
+| CounterWith7LabelsHotPath |   False |   170.32 ns |  4.907 ns | 14.392 ns |   165.91 ns | 0.0324 |     - |     - |     136 B |
+|            CounterHotPath |    True |    52.47 ns |  1.080 ns |  2.481 ns |    51.89 ns |      - |     - |     - |         - |
+| CounterWith1LabelsHotPath |    True |   142.46 ns |  2.118 ns |  1.769 ns |   142.51 ns |      - |     - |     - |         - |
+| CounterWith3LabelsHotPath |    True |   594.14 ns | 11.827 ns | 21.326 ns |   591.94 ns |      - |     - |     - |         - |
+| CounterWith5LabelsHotPath |    True |   843.52 ns | 16.612 ns | 17.775 ns |   835.77 ns | 0.0553 |     - |     - |     232 B |
+| CounterWith6LabelsHotPath |    True |   957.71 ns | 18.017 ns | 19.278 ns |   953.99 ns | 0.0629 |     - |     - |     264 B |
+| CounterWith7LabelsHotPath |    True | 1,112.38 ns | 21.805 ns | 27.576 ns | 1,104.74 ns | 0.0706 |     - |     - |     296 B |
 */
 
 namespace Benchmarks.Metrics