Backport changes affecting EventPipe from PR 38225 into C library.

src/coreclr/vm/eventing/eventpipe/ep-rt-coreclr.h

@@ -11,6 +11,7 @@
 #include "ep-session-provider.h"
 #include "fstream.h"
 #include "typestring.h"
+#include "win32threadpool.h"
 
 #undef EP_ARRAY_SIZE
 #define EP_ARRAY_SIZE(expr) (sizeof(expr) / sizeof ((expr) [0]))
@@ -1524,6 +1525,15 @@ ep_rt_config_value_get_circular_mb (void)
 	return CLRConfig::GetConfigValue (CLRConfig::INTERNAL_EventPipeCircularMB);
 }
 
+static
+inline
+bool
+ep_rt_config_value_get_use_portable_thread_pool (void)
+{
+	STATIC_CONTRACT_NOTHROW;
+	return ThreadpoolMgr::UsePortableThreadPool ();
+}
+
 /*
  * EventPipeSampleProfiler.
  */

src/mono/mono/eventpipe/ep-rt-mono.h

@@ -980,6 +980,15 @@ ep_rt_config_value_get_circular_mb (void)
 	return circular_mb;
 }
 
+static
+inline
+bool
+ep_rt_config_value_get_use_portable_thread_pool (void)
+{
+	// Only supports portable thread pool.
+	return true;
+}
+
 /*
  * EventPipeSampleProfiler.
  */

src/native/eventpipe/ep-config.c

@@ -95,8 +95,16 @@ config_register_provider (
 
 	ep_requires_lock_held ();
 
-	// See if we've already registered this provider.
-	EventPipeProvider *existing_provider = config_get_provider (config, ep_provider_get_provider_name (provider));
+	// See if we've already registered this provider. When the portable thread pool is being used, allow there to be multiple
+	// DotNETRuntime providers, as the portable thread pool temporarily uses an event source on the managed side with the same
+	// provider name.
+	// TODO: This change to allow multiple DotNETRuntime providers is temporary to get EventPipe working for
+	// PortableThreadPoolEventSource. Once a long-term solution is figured out, this change should be reverted. See
+	// https://github.com/dotnet/runtime/issues/38763 for more information.
+	EventPipeProvider *existing_provider = NULL;
+	if (!ep_rt_config_value_get_use_portable_thread_pool () || ep_rt_utf8_string_compare (ep_config_get_public_provider_name_utf8 (), ep_provider_get_provider_name (provider)) != 0)
+		existing_provider = config_get_provider (config, ep_provider_get_provider_name (provider));
+
 	if (existing_provider)
 		return false;
 

src/native/eventpipe/ep-rt.h

@@ -294,6 +294,10 @@ static
 uint32_t
 ep_rt_config_value_get_circular_mb (void);
 
+static
+bool
+ep_rt_config_value_get_use_portable_thread_pool (void);
+
 /*
  * EventPipeSampleProfiler.
  */