[browser][MT] pool don't yield to event loop

src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitems

@@ -2657,7 +2657,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)System\Threading\PortableThreadPool.ThreadCounts.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Threading\PortableThreadPool.WaitThread.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Threading\PortableThreadPool.WorkerThread.cs" />
-    <Compile Include="$(MSBuildThisFileDirectory)System\Threading\PortableThreadPool.WorkerThread.NonBrowser.cs" Condition="'$(TargetsBrowser)' != 'true'" />
+    <Compile Include="$(MSBuildThisFileDirectory)System\Threading\PortableThreadPool.WorkerThread.NonBrowser.cs" Condition="'$(TargetsBrowser)' != 'true' or '$(FeatureWasmThreads)' == 'true'" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Threading\PortableThreadPool.WorkerTracking.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Threading\PortableThreadPool.Unix.cs" Condition="'$(TargetsUnix)' == 'true' or ('$(TargetsBrowser)' == 'true' and '$(FeatureWasmThreads)' != 'true') or '$(TargetsWasi)' == 'true'" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Threading\PortableThreadPool.Windows.cs" Condition="'$(TargetsWindows)' == 'true'" />

src/libraries/System.Private.CoreLib/src/System/Threading/ThreadPool.Unix.cs

@@ -16,11 +16,9 @@ public static partial class ThreadPool
             AppContextConfigHelper.GetBooleanConfig("System.Threading.ThreadPool.EnableWorkerTracking", "DOTNET_ThreadPool_EnableWorkerTracking");
 #endif
 
-#if !(TARGET_BROWSER && FEATURE_WASM_THREADS)
         // Indicates whether the thread pool should yield the thread from the dispatch loop to the runtime periodically so that
         // the runtime may use the thread for processing other work.
         internal static bool YieldFromDispatchLoop => false;
-#endif
 
 #if !CORECLR
         internal static bool EnsureConfigInitialized() => true;

src/mono/System.Private.CoreLib/System.Private.CoreLib.csproj

@@ -273,13 +273,10 @@
   <ItemGroup Condition="('$(TargetsUnix)' == 'true' or '$(TargetsBrowser)' == 'true' or '$(TargetsWasi)' == 'true') and '$(FeaturePortableThreadPool)' == 'true'">
       <Compile Include="$(BclSourcesRoot)\System\Threading\LowLevelLifoSemaphore.Unix.Mono.cs" />
   </ItemGroup>
-  <ItemGroup Condition="('$(TargetsBrowser)' == 'true'  or '$(TargetsWasi)' == 'true') and '$(FeatureWasmThreads)' == 'true'">
+  <ItemGroup Condition="'$(TargetsBrowser)' == 'true' and '$(FeatureWasmThreads)' == 'true'">
       <Compile Include="$(BclSourcesRoot)\System\Threading\ThreadPoolBoundHandle.Browser.Threads.Mono.cs" />
       <Compile Include="$(BclSourcesRoot)\System\Threading\LowLevelLifoAsyncWaitSemaphore.Browser.Threads.Mono.cs" />
       <Compile Include="$(BclSourcesRoot)\System\Threading\PortableThreadPool.Browser.Threads.Mono.cs" />
-      <Compile Include="$(BclSourcesRoot)\System\Threading\PortableThreadPool.WorkerThread.Browser.Threads.Mono.cs" />
-      <Compile Include="$(BclSourcesRoot)\System\Threading\ThreadPool.Browser.Threads.Mono.cs" />
-      <Compile Include="$(BclSourcesRoot)\System\Threading\WebWorkerEventLoop.Browser.Threads.Mono.cs" />
   </ItemGroup>
   <ItemGroup Condition="('$(TargetsBrowser)' == 'true' or '$(TargetsWasi)' == 'true') and '$(FeatureWasmThreads)' != 'true'">
       <Compile Include="$(BclSourcesRoot)\System\Threading\ThreadPoolBoundHandle.Browser.Mono.cs" />

src/mono/System.Private.CoreLib/src/System/Threading/PortableThreadPool.Browser.Threads.Mono.cs

@@ -7,7 +7,7 @@ internal sealed partial class PortableThreadPool
 {
     private static partial class WorkerThread
     {
-        private static bool IsIOPending => WebWorkerEventLoop.HasJavaScriptInteropDependents;
+        private static bool IsIOPending => false;
     }
 
     private struct CpuUtilizationReader

src/mono/System.Private.CoreLib/src/System/Threading/ThreadPool.Browser.Mono.cs

@@ -14,7 +14,7 @@
 namespace System.Threading
 {
 #if FEATURE_WASM_THREADS
-#error when compiled with FEATURE_WASM_THREADS, we use PortableThreadPool.WorkerThread.Browser.Threads.Mono.cs
+#error when compiled with FEATURE_WASM_THREADS, we use normal unix thread pool
 #endif
     [System.Runtime.Versioning.UnsupportedOSPlatformAttribute("browser")]
     public sealed class RegisteredWaitHandle : MarshalByRefObject

src/mono/mono/metadata/icall-decl.h

@@ -191,10 +191,6 @@ ICALL_EXPORT void     ves_icall_System_Threading_LowLevelLifoSemaphore_ReleaseIn
 #if (defined(HOST_BROWSER) && !defined(DISABLE_THREADS)) || (defined(TARGET_WASM) && defined(ENABLE_ICALL_SYMBOL_MAP))
 ICALL_EXPORT gpointer ves_icall_System_Threading_LowLevelLifoAsyncWaitSemaphore_InitInternal (void);
 ICALL_EXPORT void   ves_icall_System_Threading_LowLevelLifoAsyncWaitSemaphore_PrepareAsyncWaitInternal (gpointer sem_ptr, gint32 timeout_ms, gpointer success_cb, gpointer timeout_cb, intptr_t user_data);
-
-ICALL_EXPORT MonoBoolean ves_icall_System_Threading_WebWorkerEventLoop_HasUnsettledInteropPromisesNative(void);
-ICALL_EXPORT void ves_icall_System_Threading_WebWorkerEventLoop_KeepalivePushInternal (void);
-ICALL_EXPORT void ves_icall_System_Threading_WebWorkerEventLoop_KeepalivePopInternal (void);
 #endif
 
 #ifdef TARGET_AMD64

src/mono/mono/metadata/icall-def.h

@@ -610,14 +610,6 @@ HANDLES(THREAD_10, "SetState", ves_icall_System_Threading_Thread_SetState, void,
 HANDLES(THREAD_13, "StartInternal", ves_icall_System_Threading_Thread_StartInternal, void, 2, (MonoThreadObject, gint32))
 NOHANDLES(ICALL(THREAD_14, "YieldInternal", ves_icall_System_Threading_Thread_YieldInternal))
 
-/* include these icalls if we're in the threaded wasm runtime, or if we're building a wasm-targeting cross compiler and we need to support --print-icall-table */
-#if (defined(HOST_BROWSER) && !defined(DISABLE_THREADS)) || (defined(TARGET_WASM) && defined(ENABLE_ICALL_SYMBOL_MAP))
-ICALL_TYPE(WEBWORKERLOOP, "System.Threading.WebWorkerEventLoop", WEBWORKERLOOP_1)
-NOHANDLES(ICALL(WEBWORKERLOOP_1, "HasUnsettledInteropPromisesNative", ves_icall_System_Threading_WebWorkerEventLoop_HasUnsettledInteropPromisesNative))
-NOHANDLES(ICALL(WEBWORKERLOOP_2, "KeepalivePopInternal", ves_icall_System_Threading_WebWorkerEventLoop_KeepalivePopInternal))
-NOHANDLES(ICALL(WEBWORKERLOOP_3, "KeepalivePushInternal", ves_icall_System_Threading_WebWorkerEventLoop_KeepalivePushInternal))
-#endif
-
 ICALL_TYPE(TYPE, "System.Type", TYPE_1)
 HANDLES(TYPE_1, "internal_from_handle", ves_icall_System_Type_internal_from_handle, MonoReflectionType, 1, (MonoType_ref))
 

src/mono/mono/metadata/threads.c

@@ -4958,26 +4958,6 @@ ves_icall_System_Threading_LowLevelLifoAsyncWaitSemaphore_PrepareAsyncWaitIntern
 	mono_lifo_semaphore_asyncwait_prepare_wait (sem, timeout_ms, (LifoSemaphoreAsyncWaitCallbackFn)success_cb, (LifoSemaphoreAsyncWaitCallbackFn)timedout_cb, user_data);
 }
 
-void
-ves_icall_System_Threading_WebWorkerEventLoop_KeepalivePushInternal (void)
-{
-	emscripten_runtime_keepalive_push();
-}
-
-void
-ves_icall_System_Threading_WebWorkerEventLoop_KeepalivePopInternal (void)
-{
-	emscripten_runtime_keepalive_pop();
-}
-
-extern int mono_wasm_eventloop_has_unsettled_interop_promises(void);
-
-MonoBoolean
-ves_icall_System_Threading_WebWorkerEventLoop_HasUnsettledInteropPromisesNative(void)
-{
-	return !!mono_wasm_eventloop_has_unsettled_interop_promises();
-}
-
 #endif /* HOST_BROWSER && !DISABLE_THREADS */
 
 /* for the AOT cross compiler with --print-icall-table these don't need to be callable, they just
@@ -4995,22 +4975,5 @@ ves_icall_System_Threading_LowLevelLifoAsyncWaitSemaphore_PrepareAsyncWaitIntern
 	g_assert_not_reached ();
 }
 
-void
-ves_icall_System_Threading_WebWorkerEventLoop_KeepalivePushInternal (void)
-{
-	g_assert_not_reached();
-}
-
-void
-ves_icall_System_Threading_WebWorkerEventLoop_KeepalivePopInternal (void)
-{
-	g_assert_not_reached();
-}
-
-MonoBoolean
-ves_icall_System_Threading_WebWorkerEventLoop_HasUnsettledInteropPromisesNative(void)
-{
-	g_assert_not_reached();
-}
 #endif /* defined(TARGET_WASM) && defined(ENABLE_ICALL_SYMBOL_MAP) */
 

src/mono/sample/wasm/browser-threads-minimal/main.js

@@ -12,9 +12,6 @@ try {
     const { getAssemblyExports, runMain } = await dotnet
         //.withEnvironmentVariable("MONO_LOG_LEVEL", "debug")
         //.withDiagnosticTracing(true)
-        .withConfig({
-            pthreadPoolSize: 6,
-        })
         .withElementOnExit()
         .withExitCodeLogging()
         .create();