Make counters use dedicated thread instead of timer (#25864) (#25978)

* Make a dedicated polling thread for EventCounters

* Cleanup

* remove debug prints

* nit

* Fix comment

* addressing issues from code review

* Fix an assertion from getting fired when we have multiple listeners

* Fix a test issue

* code review feedback

* Fix a potential deadlock

* Fix another deadlock

* Allow s_sleepDurationInMilliseconds to be reset to a larger value

* More issues fix

* Let thread wake up from sleep if needed

* Some suggestions for the counters fix.

The resulting behavior should be the same as what is there now (assuming I didn't mess anything up), these are all just code simplifications that hopefully make it easier to review and maintain going forward. In total I think this reduces the change size in CounterGroup.cs by ~30%.
- With the addition of the AutoResetEvent the ManualResetEvent is no longer needed, removed it.
- Removed the various if foo != null checks for the shared state, it is all initialized once when then thread is created and then assumed to be non-null elsewhere.
- Removed a 2nd lock acquisition inside OnTimer
- Replaced an if with Math.Min in PollForValues

* fix test

1 files changed, 4 insertions, 8 deletions

diff --git a/tests/src/tracing/eventcounter/eventcounter.cs b/tests/src/tracing/eventcounter/eventcounter.cs
index fffd1c8305..de1a0f0e41 100644
--- a/tests/src/tracing/eventcounter/eventcounter.cs
+++ b/tests/src/tracing/eventcounter/eventcounter.cs
@@ -76,6 +76,7 @@ namespace BasicEventSourceTests
                             if (payload.Key.Equals("Mean"))
                             {
                                 int mean = Int32.Parse(payload.Value.ToString());
+                                Console.WriteLine("Adding " + mean + " to known list of means");
                                 means.Add(mean);
                             }
                             else if (payload.Key.Equals("DisplayName"))
@@ -95,17 +96,12 @@ namespace BasicEventSourceTests
             public bool validateMean()
             {
                 // we expect to see 1 because we wrote only 1s
+                // we *might* also see 0 because there is a period of time we didn't write stuff and got callback
                 if (!means.Contains(1)) 
                 {
+                    Console.WriteLine("Mean doesn't have a 1");
                     return false;
                 }
-
-                // we also expect to see 0 because there is a period of time we didn't write stuff and got callback
-                if (!means.Contains(0)) 
-                {
-                    return false;
-                }
-
                 return true;
             }
         }
@@ -159,4 +155,4 @@ namespace BasicEventSourceTests
             }
         }
     }
-}
\ No newline at end of file
+}