add message overload warning

lualib/skynet.lua

@@ -95,6 +95,7 @@ end
 
 local coroutine_pool = {}
 local coroutine_yield = coroutine.yield
+local coroutine_count = 0
 
 local function co_create(f)
 	local co = table.remove(coroutine_pool)
@@ -109,6 +110,11 @@ local function co_create(f)
 				f(coroutine_yield())
 			end
 		end)
+		coroutine_count = coroutine_count + 1
+		if coroutine_count > 1024 then
+			skynet.error("May overload, create 1024 task")
+			coroutine_count = 0
+		end
 	else
 		coroutine.resume(co, f)
 	end

skynet-src/skynet_mq.c

@@ -15,6 +15,7 @@
 // 1 means mq is in global mq , or the message is dispatching.
 
 #define MQ_IN_GLOBAL 1
+#define MQ_OVERLOAD 1024
 
 struct message_queue {
 	uint32_t handle;
@@ -24,6 +25,8 @@ struct message_queue {
 	int lock;
 	int release;
 	int in_global;
+	int overload;
+	int overload_threshold;
 	struct skynet_message *queue;
 	struct message_queue *next;
 };
@@ -116,6 +119,8 @@ skynet_mq_create(uint32_t handle) {
 	// If the service init success, skynet_context_new will call skynet_mq_force_push to push it to global queue.
 	q->in_global = MQ_IN_GLOBAL;
 	q->release = 0;
+	q->overload = 0;
+	q->overload_threshold = MQ_OVERLOAD;
 	q->queue = skynet_malloc(sizeof(struct skynet_message) * q->cap);
 	q->next = NULL;
 
@@ -150,17 +155,42 @@ skynet_mq_length(struct message_queue *q) {
 	return tail + cap - head;
 }
 
+int
+skynet_mq_overload(struct message_queue *q) {
+	if (q->overload) {
+		int overload = q->overload;
+		q->overload = 0;
+		return overload;
+	} 
+	return 0;
+}
+
 int
 skynet_mq_pop(struct message_queue *q, struct skynet_message *message) {
 	int ret = 1;
 	LOCK(q)
 
 	if (q->head != q->tail) {
-		*message = q->queue[q->head];
+		*message = q->queue[q->head++];
 		ret = 0;
-		if ( ++ q->head >= q->cap) {
+		int head = q->head;
-			q->head = 0;
+		int tail = q->tail;
+		int cap = q->cap;
+
+		if (head >= cap) {
+			q->head = head = 0;
 		}
+		int length = tail - head;
+		if (length < 0) {
+			length += cap;
+		}
+		while (length > q->overload_threshold) {
+			q->overload = length;
+			q->overload_threshold *= 2;
+		}
+	} else {
+		// reset overload_threshold when queue is empty
+		q->overload_threshold = MQ_OVERLOAD;
 	}
 
 	if (ret) {

skynet-src/skynet_mq.h

@@ -30,6 +30,7 @@ void skynet_mq_push(struct message_queue *q, struct skynet_message *message);
 
 // return the length of message queue, for debug
 int skynet_mq_length(struct message_queue *q);
+int skynet_mq_overload(struct message_queue *q);
 
 void skynet_mq_init();
 

skynet-src/skynet_server.c

@@ -283,6 +283,10 @@ skynet_context_message_dispatch(struct skynet_monitor *sm, struct message_queue
 			n = skynet_mq_length(q);
 			n >>= weight;
 		}
+		int overload = skynet_mq_overload(q);
+		if (overload) {
+			skynet_error(ctx, "May overload, message queue length = %d", overload);
+		}
 
 		skynet_monitor_trigger(sm, msg.source , handle);
 

test/testoverload.lua

@@ -0,0 +1,44 @@
+local skynet = require "skynet"
+
+local mode = ...
+
+if mode == "slave" then
+
+local CMD = {}
+
+function CMD.sum(n)
+	skynet.error("for loop begin")
+	local s = 0
+	for i = 1, n do
+		s = s + i
+	end
+	skynet.error("for loop end")
+end
+
+function CMD.blackhole()
+end
+
+skynet.start(function()
+	skynet.dispatch("lua", function(_,_, cmd, ...)
+		local f = CMD[cmd]
+		f(...)
+	end)
+end)
+
+else
+
+skynet.start(function()
+	local slave = skynet.newservice(SERVICE_NAME, "slave")
+	for step = 1, 20 do
+		skynet.error("overload test ".. step)
+		for i = 1, 512 * step do
+			skynet.send(slave, "lua", "blackhole")
+		end
+		skynet.sleep(step)
+	end
+	local n = 1000000000
+	skynet.error(string.format("endless test n=%d", n))
+	skynet.send(slave, "lua", "sum", n)
+end)
+
+end