From 5b391396f199bb1f3fd175c9712ecef840ab1fa9 Mon Sep 17 00:00:00 2001
From: David Mason <davmason@microsoft.com>
Date: Thu, 23 Mar 2023 02:48:28 -0700
Subject: [PATCH] Treat enable with interval as 0 as disable

---
 .../Diagnostics/Tracing/CounterGroup.cs       | 21 ++++++++++++-------
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/src/libraries/System.Private.CoreLib/src/System/Diagnostics/Tracing/CounterGroup.cs b/src/libraries/System.Private.CoreLib/src/System/Diagnostics/Tracing/CounterGroup.cs
index 7a50a35c7e9a4..a39717f1d840d 100644
--- a/src/libraries/System.Private.CoreLib/src/System/Diagnostics/Tracing/CounterGroup.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/Diagnostics/Tracing/CounterGroup.cs
@@ -53,9 +53,7 @@ private void OnEventSourceCommand(object? sender, EventCommandEventArgs e)
                 if (e.Command == EventCommand.Enable)
                 {
                     Debug.Assert(e.Arguments != null);
-                    Debug.Assert(_refCount >= 0);
 
-                    ++_refCount;
                     float intervalValue = 1.0f;
                     if (e.Arguments.TryGetValue("EventCounterIntervalSec", out string? valueStr)
                         && float.TryParse(valueStr, out float value))
@@ -63,7 +61,18 @@ private void OnEventSourceCommand(object? sender, EventCommandEventArgs e)
                         intervalValue = value;
                     }
 
-                    EnableTimer(intervalValue);
+                    if (intervalValue > 0)
+                    {
+                        Debug.Assert(_refCount >= 0);
+                        ++_refCount;
+                        EnableTimer(intervalValue);
+                    }
+                    else
+                    {
+                        Debug.Assert(_refCount >= 1);
+                        --_refCount;
+                        DisableTimer();
+                    }
                 }
                 else if (e.Command == EventCommand.Disable)
                 {
@@ -140,11 +149,7 @@ internal static CounterGroup GetCounterGroup(EventSource eventSource)
         private void EnableTimer(float pollingIntervalInSeconds)
         {
             Debug.Assert(Monitor.IsEntered(s_counterGroupLock));
-            if (pollingIntervalInSeconds <= 0)
-            {
-                DisableTimer();
-            }
-            else if (_pollingIntervalInMilliseconds == 0 || pollingIntervalInSeconds * 1000 < _pollingIntervalInMilliseconds)
+            if (pollingIntervalInSeconds * 1000 < _pollingIntervalInMilliseconds)
             {
                 _pollingIntervalInMilliseconds = (int)(pollingIntervalInSeconds * 1000);
                 ResetCounters(); // Reset statistics for counters before we start the thread.