From e9e1a3e80d93666e1054561f244093da84e63bde Mon Sep 17 00:00:00 2001
From: Cory McWilliams <cory@unprompted.com>
Date: Mon, 17 Jan 2022 01:29:35 +0000
Subject: [PATCH] Trace libuv's idle time metric.

git-svn-id: https://www.unprompted.com/svn/projects/tildefriends/trunk@3772 ed5197a5-7fde-0310-b194-c3ffbd925b24
---
 src/task.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/task.c b/src/task.c
index 23f97e30..374e51f5 100644
--- a/src/task.c
+++ b/src/task.c
@@ -94,7 +94,10 @@ typedef struct _tf_task_t
 	int _promise_count;
 	promiseid_t _nextPromise;
 	uv_loop_t _loop;
+
 	uv_timer_t trace_timer;
+	uint64_t last_hrtime;
+	uint64_t last_idle_time;
 
 	export_record_t** _exports;
 	int _export_count;
@@ -1239,12 +1242,15 @@ static void _tf_task_promise_rejection_tracker(JSContext* context, JSValueConst
 static void _tf_task_trace_timer(uv_timer_t* timer)
 {
 	tf_task_t* task = timer->data;
+	uint64_t hrtime = uv_hrtime();
+	uint64_t idle_time = uv_metrics_idle_time(&task->_loop);
 	const char* k_names[] =
 	{
 		"child_tasks",
 		"imports",
 		"exports",
 		"promises",
+		"idle_percent",
 	};
 	int64_t values[] =
 	{
@@ -1252,7 +1258,10 @@ static void _tf_task_trace_timer(uv_timer_t* timer)
 		task->_import_count,
 		task->_export_count,
 		task->_promise_count,
+		(hrtime - task->last_hrtime) ? 100LL * (idle_time - task->last_idle_time) / (hrtime - task->last_hrtime) : 0,
 	};
+	task->last_hrtime = hrtime;
+	task->last_idle_time = idle_time;
 	tf_trace_counter(task->_trace, "task", sizeof(k_names) / sizeof(*k_names), k_names, values);
 }
 
@@ -1278,6 +1287,7 @@ tf_task_t* tf_task_create()
 	JS_NewClass(task->_runtime, _import_class_id, &def);
 	task->_loadedFiles = JS_NewObject(task->_context);
 	uv_loop_init(&task->_loop);
+	uv_loop_configure(&task->_loop, UV_METRICS_IDLE_TIME);
 	task->_loop.data = task;
 	task->trace_timer.data = task;
 	uv_timer_init(&task->_loop, &task->trace_timer);