Index: share/man/man4/sfxge.4
===================================================================
--- share/man/man4/sfxge.4
+++ share/man/man4/sfxge.4
@@ -108,6 +108,10 @@
 .Va tx_early_drops
 counter is incremented and the local sender receives ENOBUFS.
 The value must be greater than or equal to 0.
+.It Va hw.sfxge.N.max_rss_channels
+The maximum number of allocated RSS channels for the Nth adapter.
+If set to 0 or unset, the number of channels is determined by the number
+of CPU cores.
 .El
 .Sh SUPPORT
 For general information and support,
Index: sys/dev/sfxge/sfxge.h
===================================================================
--- sys/dev/sfxge/sfxge.h
+++ sys/dev/sfxge/sfxge.h
@@ -228,6 +228,7 @@
 	clock_t				ev_stats_update_time;
 	uint64_t			ev_stats[EV_NQSTATS];
 
+	unsigned int			max_rss_channels;
 	uma_zone_t			rxq_cache;
 	struct sfxge_rxq		*rxq[SFXGE_RX_SCALE_MAX];
 	unsigned int			rx_indir_table[SFXGE_RX_SCALE_MAX];
Index: sys/dev/sfxge/sfxge.c
===================================================================
--- sys/dev/sfxge/sfxge.c
+++ sys/dev/sfxge/sfxge.c
@@ -397,11 +397,18 @@
 	device_t dev;
 	efx_nic_t *enp;
 	int error;
+	char rss_param_name[sizeof(SFXGE_PARAM(%d.max_rss_channels))];
 
 	dev = sc->dev;
 
 	sx_init(&sc->softc_lock, "sfxge_softc");
 
+	sc->max_rss_channels = 0;
+	snprintf(rss_param_name, sizeof(rss_param_name),
+		 SFXGE_PARAM(%d.max_rss_channels),
+		 (int)device_get_unit(dev));
+	TUNABLE_INT_FETCH(rss_param_name, &sc->max_rss_channels);
+
 	sc->stats_node = SYSCTL_ADD_NODE(
 		device_get_sysctl_ctx(dev),
 		SYSCTL_CHILDREN(device_get_sysctl_tree(dev)),
Index: sys/dev/sfxge/sfxge_intr.c
===================================================================
--- sys/dev/sfxge/sfxge_intr.c
+++ sys/dev/sfxge/sfxge_intr.c
@@ -303,6 +303,9 @@
 	if (count > EFX_MAXRSS)
 		count = EFX_MAXRSS;
 
+	if (sc->max_rss_channels > 0 && count > sc->max_rss_channels)
+		count = sc->max_rss_channels;
+
 	rid = PCIR_BAR(4);
 	resp = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid, RF_ACTIVE);
 	if (resp == NULL)