Add thread that runs libuv loop continuously

.gitignore

@@ -36,6 +36,7 @@
 .vscode/*
 *.heapsnapshot
 .cache
+*.lit_test_times.txt
 # Buildkite: Ignore the entire .buildkite directory
 /.buildkite
 

base/Base.jl

@@ -634,7 +634,12 @@ function __init__()
     @static if !Sys.iswindows()
         # triggering a profile via signals is not implemented on windows
         cond = Base.AsyncCondition()
+        Base.iolock_begin() # uv_unref needs lock
         Base.uv_unref(cond.handle)
+        Base.iolock_end()
+        PROFILE_PRINT_COND[] = cond
+        ccall(:jl_set_peek_cond, Cvoid, (Ptr{Cvoid},), PROFILE_PRINT_COND[].handle)
+        errormonitor(Threads.@spawn(profile_printing_listener()))
         t = errormonitor(Threads.@spawn(profile_printing_listener(cond)))
         atexit() do
             # destroy this callback when exiting

base/lock.jl

@@ -435,10 +435,10 @@ This provides an acquire & release memory ordering on notify/wait.
     The `autoreset` functionality and memory ordering guarantee requires at least Julia 1.8.
 """
 mutable struct Event
-    const notify::ThreadSynchronizer
-    const autoreset::Bool
+    notify::Threads.Condition
+    autoreset::Bool
     @atomic set::Bool
-    Event(autoreset::Bool=false) = new(ThreadSynchronizer(), autoreset, false)
+    Event(autoreset::Bool=false) = new(Threads.Condition(), autoreset, false)
 end
 
 function wait(e::Event)

base/task.jl

@@ -997,7 +997,6 @@ function wait()
     W = workqueue_for(Threads.threadid())
     poptask(W)
     result = try_yieldto(ensure_rescheduled)
-    process_events()
     # return when we come out of the queue
     return result
 end

base/threadingconstructs.jl

@@ -144,8 +144,26 @@ This includes both mark threads and concurrent sweep threads.
 """
 ngcthreads() = Int(unsafe_load(cglobal(:jl_n_gcthreads, Cint))) + 1
 
+# Atomic is not available here and soft-deprecated
+mutable struct ThreadedRegion
+    @atomic counter::UInt
+end
+const THREADED_REGION = ThreadedRegion(UInt(0))
+
+in_threaded_region() = THREADED_REGION.counter != 0
+
+function enter_threaded_region()
+    @atomic THREADED_REGION.counter += 1
+    return nothing
+end
+
+function exit_threaded_region()
+    @atomic THREADED_REGION.counter -= 1
+    return nothing
+end
+
 function threading_run(fun, static)
-    ccall(:jl_enter_threaded_region, Cvoid, ())
+    enter_threaded_region()
     n = threadpoolsize()
     tid_offset = threadpoolsize(:interactive)
     tasks = Vector{Task}(undef, n)
@@ -165,7 +183,7 @@ function threading_run(fun, static)
     for i = 1:n
         Base._wait(tasks[i])
     end
-    ccall(:jl_exit_threaded_region, Cvoid, ())
+    exit_threaded_region()
     failed_tasks = filter!(istaskfailed, tasks)
     if !isempty(failed_tasks)
         throw(CompositeException(map(TaskFailedException, failed_tasks)))
@@ -217,7 +235,7 @@ function _threadsfor(iter, lbody, schedule)
         end
         if $(schedule === :dynamic || schedule === :default)
             threading_run(threadsfor_fun, false)
-        elseif ccall(:jl_in_threaded_region, Cint, ()) != 0 # :static
+        elseif in_threaded_region() # :static
             error("`@threads :static` cannot be used concurrently or nested")
         else # :static
             threading_run(threadsfor_fun, true)

src/gc.c

@@ -232,8 +232,7 @@ void jl_gc_wait_for_the_world(jl_ptls_t* gc_all_tls_states, int gc_n_threads)
     TracyCZoneColor(ctx, 0x696969);
 #endif
     assert(gc_n_threads);
-    if (gc_n_threads > 1)
-        jl_wake_libuv();
+    jl_wake_libuv();
     for (int i = 0; i < gc_n_threads; i++) {
         jl_ptls_t ptls2 = gc_all_tls_states[i];
         if (ptls2 != NULL) {

src/init.c

@@ -150,7 +150,7 @@ static void jl_uv_exitcleanup_add(uv_handle_t *handle, struct uv_shutdown_queue
     queue->last = item;
 }
 
-static void jl_uv_exitcleanup_walk(uv_handle_t *handle, void *arg)
+static void jl_uv_cb_exitcleanup_walk(uv_handle_t *handle, void *arg)
 {
     jl_uv_exitcleanup_add(handle, (struct uv_shutdown_queue*)arg);
 }
@@ -302,7 +302,7 @@ JL_DLLEXPORT void jl_atexit_hook(int exitcode) JL_NOTSAFEPOINT_ENTER
     if (loop != NULL) {
         struct uv_shutdown_queue queue = {NULL, NULL};
         JL_UV_LOCK();
-        uv_walk(loop, jl_uv_exitcleanup_walk, &queue);
+        uv_walk(loop, jl_uv_cb_exitcleanup_walk, &queue);
         struct uv_shutdown_queue_item *item = queue.first;
         if (ct) {
             while (item) {

src/jl_exported_funcs.inc

@@ -108,7 +108,6 @@
     XX(jl_egal__bitstag) \
     XX(jl_eh_restore_state) \
     XX(jl_enter_handler) \
-    XX(jl_enter_threaded_region) \
     XX(jl_environ) \
     XX(jl_eof_error) \
     XX(jl_eqtable_get) \
@@ -124,7 +123,6 @@
     XX(jl_excstack_state) \
     XX(jl_exit) \
     XX(jl_exit_on_sigint) \
-    XX(jl_exit_threaded_region) \
     XX(jl_expand) \
     XX(jl_expand_and_resolve) \
     XX(jl_expand_stmt) \
@@ -259,7 +257,6 @@
     XX(jl_intrinsic_name) \
     XX(jl_invoke) \
     XX(jl_invoke_api) \
-    XX(jl_in_threaded_region) \
     XX(jl_iolock_begin) \
     XX(jl_iolock_end) \
     XX(jl_ios_buffer_n) \