TTL reads could be fewer.

Specifically, we don't need to read the atomic value each loop
iteration.  We can just get it when a message is first received,
and then use that value.  This should make receiving through proxies
a little more efficient.

4 files changed, 13 insertions, 7 deletions

diff --git a/src/protocol/reqrep0/rep.c b/src/protocol/reqrep0/rep.c
index 3cc1802a..b546044d 100644
--- a/src/protocol/reqrep0/rep.c
+++ b/src/protocol/reqrep0/rep.c
@@ -491,6 +491,7 @@ rep0_pipe_recv_cb(void *arg)
 	nni_aio *  aio;
 	size_t     len;
 	int        hops;
+	int        ttl;
 
 	if (nni_aio_result(&p->aio_recv) != 0) {
 		nni_pipe_close(p->pipe);
@@ -498,6 +499,7 @@ rep0_pipe_recv_cb(void *arg)
 	}
 
 	msg = nni_aio_get_msg(&p->aio_recv);
+	ttl = nni_atomic_get(&s->ttl);
 
 	nni_msg_set_pipe(msg, p->id);
 
@@ -506,7 +508,7 @@ rep0_pipe_recv_cb(void *arg)
 	for (;;) {
 		bool end;
 
-		if (hops > nni_atomic_get(&s->ttl)) {
+		if (hops > ttl) {
 			// This isn't malformed, but it has gone
 			// through too many hops.  Do not disconnect,
 			// because we can legitimately receive messages
@@ -577,8 +579,8 @@ static int
 rep0_sock_set_max_ttl(void *arg, const void *buf, size_t sz, nni_opt_type t)
 {
 	rep0_sock *s = arg;
-	int ttl;
-	int rv;
+	int        ttl;
+	int        rv;
 
 	if ((rv = nni_copyin_int(&ttl, buf, sz, 1, 255, t)) == 0) {
 		nni_atomic_set(&s->ttl, ttl);
diff --git a/src/protocol/reqrep0/xrep.c b/src/protocol/reqrep0/xrep.c
index e5d96f02..a036e6f6 100644
--- a/src/protocol/reqrep0/xrep.c
+++ b/src/protocol/reqrep0/xrep.c
@@ -283,12 +283,15 @@ xrep0_pipe_recv_cb(void *arg)
 	xrep0_sock *s = p->rep;
 	nni_msg *   msg;
 	int         hops;
+	int         ttl;
 
 	if (nni_aio_result(&p->aio_recv) != 0) {
 		nni_pipe_close(p->pipe);
 		return;
 	}
 
+	ttl = nni_atomic_get(&s->ttl);
+
 	msg = nni_aio_get_msg(&p->aio_recv);
 	nni_aio_set_msg(&p->aio_recv, NULL);
 
@@ -302,7 +305,7 @@ xrep0_pipe_recv_cb(void *arg)
 	for (;;) {
 		bool     end = 0;
 		uint8_t *body;
-		if (hops > (int)nni_atomic_get(&s->ttl)) {
+		if (hops > ttl) {
 			// This isn't malformed, but it has gone through
 			// too many hops.  Do not disconnect, because we
 			// can legitimately receive messages with too many
diff --git a/src/protocol/survey0/respond.c b/src/protocol/survey0/respond.c
index 201811de..19dedef0 100644
--- a/src/protocol/survey0/respond.c
+++ b/src/protocol/survey0/respond.c
@@ -480,12 +480,14 @@ resp0_pipe_recv_cb(void *arg)
 	nni_aio *   aio;
 	int         hops;
 	size_t      len;
+	int         ttl;
 
 	if (nni_aio_result(&p->aio_recv) != 0) {
 		nni_pipe_close(p->npipe);
 		return;
 	}
 
+	ttl = nni_atomic_get(&s->ttl);
 	msg = nni_aio_get_msg(&p->aio_recv);
 	nni_msg_set_pipe(msg, p->id);
 
@@ -495,7 +497,7 @@ resp0_pipe_recv_cb(void *arg)
 		bool     end = 0;
 		uint8_t *body;
 
-		if (hops > nni_atomic_get(&s->ttl)) {
+		if (hops > ttl) {
 			goto drop;
 		}
 		hops++;
diff --git a/src/protocol/survey0/xrespond.c b/src/protocol/survey0/xrespond.c
index 65bd047e..73e541d3 100644
--- a/src/protocol/survey0/xrespond.c
+++ b/src/protocol/survey0/xrespond.c
@@ -273,13 +273,12 @@ xresp0_recv_cb(void *arg)
 	int          hops;
 	int          ttl;
 
-	ttl = nni_atomic_get(&s->ttl);
-
 	if (nni_aio_result(p->aio_recv) != 0) {
 		nni_pipe_close(p->npipe);
 		return;
 	}
 
+	ttl = nni_atomic_get(&s->ttl);
 	msg = nni_aio_get_msg(p->aio_recv);
 	nni_aio_set_msg(p->aio_recv, NULL);
 	nni_msg_set_pipe(msg, p->id);