Index: sys/net/rss_config.h
===================================================================
--- sys/net/rss_config.h
+++ sys/net/rss_config.h
@@ -93,6 +93,24 @@
 #define	RSS_HASH_PKT_EGRESS	1
 
 /*
+ * Rate limited debugging routine.
+ */
+#define	RSS_DEBUG(lps, format, ...)	do {				\
+	if (rss_debug) {						\
+		static int t0, __cnt;					\
+		if (t0 != time_second) {				\
+			t0 = time_second;				\
+			__cnt = 0;					\
+		}							\
+		if (__cnt++ < lps)					\
+			printf("RSS (%s:%u): " format, __func__, __LINE__,\
+			    ##__VA_ARGS__);				\
+	}								\
+} while (0)
+
+extern int	rss_debug;
+
+/*
  * Device driver interfaces to query RSS properties that must be programmed
  * into hardware.
  */
Index: sys/net/rss_config.c
===================================================================
--- sys/net/rss_config.c
+++ sys/net/rss_config.c
@@ -152,6 +152,15 @@
     __DECONST(int *, &rss_basecpu), 0, "RSS base CPU");
 
 /*
+ * Print verbose debugging messages.
+ * 0 - disable
+ * non-zero - enable
+ */
+int	rss_debug = 0;
+SYSCTL_INT(_net_inet_rss, OID_AUTO, debug, CTLFLAG_RWTUN, &rss_debug, 0,
+    "RSS debug level");
+
+/*
  * RSS secret key, intended to prevent attacks on load-balancing.  Its
  * effectiveness may be limited by algorithm choice and available entropy
  * during the boot.
@@ -194,8 +203,8 @@
 		break;
 
 	default:
-		printf("%s: invalid RSS hashalgo %u, coercing to %u",
-		    __func__, rss_hashalgo, RSS_HASH_TOEPLITZ);
+		RSS_DEBUG(5, "invalid RSS hashalgo %u, coercing to %u\n",
+		    rss_hashalgo, RSS_HASH_TOEPLITZ);
 		rss_hashalgo = RSS_HASH_TOEPLITZ;
 	}
 
@@ -229,8 +238,8 @@
 		 * ones.
 		 */
 		if (rss_bits == 0 || rss_bits > RSS_MAXBITS) {
-			printf("%s: RSS bits %u not valid, coercing to  %u",
-			    __func__, rss_bits, RSS_MAXBITS);
+			RSS_DEBUG(5, "RSS bits %u not valid, coercing to %u\n",
+			    rss_bits, RSS_MAXBITS);
 			rss_bits = RSS_MAXBITS;
 		}
 
@@ -241,9 +250,8 @@
 		 */
 		rss_buckets = (1 << rss_bits);
 		if (rss_buckets < rss_ncpus)
-			printf("%s: WARNING: rss_buckets (%u) less than "
-			    "rss_ncpus (%u)\n", __func__, rss_buckets,
-			    rss_ncpus);
+			RSS_DEBUG(5, "WARNING: rss_buckets (%u) less than "
+			    "rss_ncpus (%u)\n", rss_buckets, rss_ncpus);
 		rss_mask = rss_buckets - 1;
 	} else {
 		rss_bits = 0;
Index: sys/netinet/in_rss.c
===================================================================
--- sys/netinet/in_rss.c
+++ sys/netinet/in_rss.c
@@ -147,7 +147,7 @@
 	}
 
 	/* No configured available hashtypes! */
-	printf("%s: no available hashtypes!\n", __func__);
+	RSS_DEBUG(5, "no available hashtypes!\n");
 	return (-1);
 }
 
@@ -183,7 +183,7 @@
 	 * XXX For now this only handles hashing on incoming mbufs.
 	 */
 	if (dir != RSS_HASH_PKT_INGRESS) {
-		printf("%s: called on EGRESS packet!\n", __func__);
+		RSS_DEBUG(5, "called on EGRESS packet!\n");
 		return (-1);
 	}
 
@@ -192,11 +192,11 @@
 	 * to have an IPv4 header in it.
 	 */
 	if (m->m_pkthdr.len < (sizeof(struct ip))) {
-		printf("%s: short mbuf pkthdr\n", __func__);
+		RSS_DEBUG(5, "short mbuf pkthdr\n");
 		return (-1);
 	}
 	if (m->m_len < (sizeof(struct ip))) {
-		printf("%s: short mbuf len\n", __func__);
+		RSS_DEBUG(5, "short mbuf len\n");
 		return (-1);
 	}
 
@@ -280,7 +280,7 @@
 	    (proto == IPPROTO_TCP) &&
 	    (is_frag == 0)) {
 		if (m->m_len < iphlen + sizeof(struct tcphdr)) {
-			printf("%s: short TCP frame?\n", __func__);
+			RSS_DEBUG(5, "short TCP frame?\n");
 			return (-1);
 		}
 		th = (const struct tcphdr *)((c_caddr_t)ip + iphlen);
@@ -295,7 +295,7 @@
 	    (is_frag == 0)) {
 		uh = (const struct udphdr *)((c_caddr_t)ip + iphlen);
 		if (m->m_len < iphlen + sizeof(struct udphdr)) {
-			printf("%s: short UDP frame?\n", __func__);
+			RSS_DEBUG(5, "short UDP frame?\n");
 			return (-1);
 		}
 		return rss_proto_software_hash_v4(ip->ip_src, ip->ip_dst,
@@ -313,7 +313,7 @@
 		    hashval,
 		    hashtype);
 	} else {
-		printf("%s: no available hashtypes!\n", __func__);
+		RSS_DEBUG(5, "no available hashtypes!\n");
 		return (-1);
 	}
 }
Index: sys/netinet6/in6_rss.c
===================================================================
--- sys/netinet6/in6_rss.c
+++ sys/netinet6/in6_rss.c
@@ -147,6 +147,6 @@
 	}
 
 	/* No configured available hashtypes! */
-	printf("%s: no available hashtypes!\n", __func__);
+	RSS_DEBUG(5, "no available hashtypes!\n");
 	return (-1);
 }