TT#101202 keep timer queue entries with same timestamp in order

closes #1110

Change-Id: Ia121deb9589bfdfa112189b22d4a78bdb29c535b

daemon/timerthread.c

@@ -158,7 +158,14 @@ static void __timerthread_queue_free(void *p) {
 static int ttqe_compare(const void *a, const void *b) {
 	const struct timerthread_queue_entry *t1 = a;
 	const struct timerthread_queue_entry *t2 = b;
-	return timeval_cmp_ptr(&t1->when, &t2->when);
+	int ret = timeval_cmp_zero(&t1->when, &t2->when);
+	if (ret)
+		return ret;
+	if (t1->idx < t2->idx)
+		return -1;
+	if (t1->idx == t2->idx)
+		return 0;
+	return 1;
 }
  
 void *timerthread_queue_new(const char *type, size_t size,
@@ -183,6 +190,18 @@ void *timerthread_queue_new(const char *type, size_t size,
 	return ttq;
 }
 
+int __ttqe_find_last_idx(const void *a, const void *b) {
+	const struct timerthread_queue_entry *ttqe_a = a;
+	void **data = (void **) b;
+	const struct timerthread_queue_entry *ttqe_b = data[0];
+	int ret = timeval_cmp(&ttqe_b->when, &ttqe_a->when);
+	if (ret)
+		return ret;
+	// same timestamp. track highest seen idx
+	if (GPOINTER_TO_UINT(data[1]) < ttqe_a->idx)
+		data[1] = GUINT_TO_POINTER(ttqe_a->idx);
+	return 1; // and continue to higher idx
+}
 void timerthread_queue_push(struct timerthread_queue *ttq, struct timerthread_queue_entry *ttqe) {
 	// can we send immediately?
 	if (ttq->run_now_func && timerthread_queue_run_one(ttq, ttqe, ttq->run_now_func) == 0)
@@ -203,7 +222,22 @@ void timerthread_queue_push(struct timerthread_queue *ttq, struct timerthread_qu
 //			ntohs(rh->seq_num),
 //			ntohl(rh->timestamp));
 
+	ttqe->idx = 0;
+
 	mutex_lock(&ttq->lock);
+
+	// check for most common case: no timestamp collision exists
+	if (!g_tree_lookup(ttq->entries, ttqe))
+		;
+	else {
+		// something else exists with the same timestamp. find the highest idx
+		void *data[2];
+		data[0] = ttqe;
+		data[1] = 0;
+		g_tree_search(ttq->entries, __ttqe_find_last_idx, data);
+		ttqe->idx = GPOINTER_TO_UINT(data[1] + 1);
+	}
+
 	// this hands over ownership of cp, so we must copy the timeval out
 	struct timeval tv_send = ttqe->when;
 	g_tree_insert(ttq->entries, ttqe, ttqe);

include/timerthread.h

@@ -35,6 +35,7 @@ struct timerthread_queue {
 
 struct timerthread_queue_entry {
 	struct timeval when;
+	unsigned int idx; // for equal timestamps
 	void *source; // opaque
 	char __rest[0];
 };

lib/auxlib.c

@@ -363,9 +363,8 @@ int uint32_eq(const void *a, const void *b) {
 	return (*A == *B) ? TRUE : FALSE;
 }
 
-int timeval_cmp_ptr(const void *a, const void *b) {
+int timeval_cmp_zero(const void *a, const void *b) {
 	const struct timeval *A = a, *B = b;
-	int ret;
 
 	/* zero timevals go last */
 	if (A->tv_sec == 0 && B->tv_sec != 0)
@@ -373,13 +372,18 @@ int timeval_cmp_ptr(const void *a, const void *b) {
 	if (B->tv_sec == 0 && A->tv_sec == 0)
 		return -1;
 	if (A->tv_sec == 0 && B->tv_sec == 0)
-		goto ptr;
+		return 0;
 	/* earlier timevals go first */
-	ret = timeval_cmp(A, B);
+	return timeval_cmp(A, B);
+}
+
+int timeval_cmp_ptr(const void *a, const void *b) {
+	const struct timeval *A = a, *B = b;
+	int ret;
+	ret = timeval_cmp_zero(A, B);
 	if (ret)
 		return ret;
 	/* equal timeval, so use pointer as tie breaker */
-ptr:
 	if (A < B)
 		return -1;
 	if (A > B)

lib/auxlib.h

@@ -260,6 +260,7 @@ INLINE int timeval_cmp(const struct timeval *a, const struct timeval *b) {
 	return long_cmp(a->tv_usec, b->tv_usec);
 }
 // as a GCompareFunc
+int timeval_cmp_zero(const void *a, const void *b);
 int timeval_cmp_ptr(const void *a, const void *b);
 
 INLINE void timeval_lowest(struct timeval *l, const struct timeval *n) {