if_lem.c: make sure that lem_rxeof() can drain the entire rx queue

	irrespective of the setting of lem_rx_process_limit, while
	giving a chance to the taskqueue scheduler to act after
	each chunk.
	This makes lem_rxeof similar to the one in if_em.c and if_igb.c .

if_lem.c and if_em.c: add a sysctl to manually configure the
	'itr' moderation register.

Approved by:	Jack Vogel

4 files changed, 27 insertions, 5 deletions

diff --git a/sys/dev/e1000/if_em.c b/sys/dev/e1000/if_em.c
index b210d4e..2ca4d3e 100644
--- a/sys/dev/e1000/if_em.c
+++ b/sys/dev/e1000/if_em.c
@@ -335,6 +335,9 @@ MODULE_DEPEND(em, ether, 1, 1, 1);
 #define EM_USECS_TO_TICKS(usecs)	((1000 * (usecs) + 512) / 1024)
 #define M_TSO_LEN			66
 
+#define MAX_INTS_PER_SEC	8000
+#define DEFAULT_ITR		(1000000000/(MAX_INTS_PER_SEC * 256))
+
 /* Allow common code without TSO */
 #ifndef CSUM_TSO
 #define CSUM_TSO	0
@@ -570,6 +573,11 @@ em_attach(device_t dev)
 	    &adapter->tx_abs_int_delay,
 	    E1000_REGISTER(hw, E1000_TADV),
 	    em_tx_abs_int_delay_dflt);
+	em_add_int_delay_sysctl(adapter, "itr",
+	    "interrupt delay limit in usecs/4",
+	    &adapter->tx_itr,
+	    E1000_REGISTER(hw, E1000_ITR),
+	    DEFAULT_ITR);
 
 	/* Sysctl for limiting the amount of work done in the taskqueue */
 	em_set_sysctl_value(adapter, "rx_processing_limit",
@@ -4271,8 +4279,6 @@ em_free_receive_buffers(struct rx_ring *rxr)
  *  Enable receive unit.
  *
  **********************************************************************/
-#define MAX_INTS_PER_SEC	8000
-#define DEFAULT_ITR	     1000000000/(MAX_INTS_PER_SEC * 256)
 
 static void
 em_initialize_receive_unit(struct adapter *adapter)
@@ -5618,6 +5624,8 @@ em_sysctl_int_delay(SYSCTL_HANDLER_ARGS)
 		return (EINVAL);
 	info->value = usecs;
 	ticks = EM_USECS_TO_TICKS(usecs);
+	if (info->offset == E1000_ITR)	/* units are 256ns here */
+		ticks *= 4;
 
 	adapter = info->adapter;
 	
diff --git a/sys/dev/e1000/if_em.h b/sys/dev/e1000/if_em.h
index f1afbad..09d81d2 100644
--- a/sys/dev/e1000/if_em.h
+++ b/sys/dev/e1000/if_em.h
@@ -429,6 +429,7 @@ struct adapter {
 	struct em_int_delay_info tx_abs_int_delay;
 	struct em_int_delay_info rx_int_delay;
 	struct em_int_delay_info rx_abs_int_delay;
+	struct em_int_delay_info tx_itr;
 
 	/* Misc stats maintained by the driver */
 	unsigned long	dropped_pkts;
diff --git a/sys/dev/e1000/if_lem.c b/sys/dev/e1000/if_lem.c
index 0ecf651..553aeef 100644
--- a/sys/dev/e1000/if_lem.c
+++ b/sys/dev/e1000/if_lem.c
@@ -281,6 +281,9 @@ MODULE_DEPEND(lem, ether, 1, 1, 1);
 #define EM_TICKS_TO_USECS(ticks)	((1024 * (ticks) + 500) / 1000)
 #define EM_USECS_TO_TICKS(usecs)	((1000 * (usecs) + 512) / 1024)
 
+#define MAX_INTS_PER_SEC	8000
+#define DEFAULT_ITR		(1000000000/(MAX_INTS_PER_SEC * 256))
+
 static int lem_tx_int_delay_dflt = EM_TICKS_TO_USECS(EM_TIDV);
 static int lem_rx_int_delay_dflt = EM_TICKS_TO_USECS(EM_RDTR);
 static int lem_tx_abs_int_delay_dflt = EM_TICKS_TO_USECS(EM_TADV);
@@ -442,6 +445,11 @@ lem_attach(device_t dev)
 		    &adapter->tx_abs_int_delay,
 		    E1000_REGISTER(&adapter->hw, E1000_TADV),
 		    lem_tx_abs_int_delay_dflt);
+		lem_add_int_delay_sysctl(adapter, "itr",
+		    "interrupt delay limit in usecs/4",
+		    &adapter->tx_itr,
+		    E1000_REGISTER(&adapter->hw, E1000_ITR),
+		    DEFAULT_ITR);
 	}
 
 	/* Sysctls for limiting the amount of work done in the taskqueue */
@@ -1337,12 +1345,16 @@ lem_handle_rxtx(void *context, int pending)
 
 
 	if (ifp->if_drv_flags & IFF_DRV_RUNNING) {
-		lem_rxeof(adapter, adapter->rx_process_limit, NULL);
+		bool more = lem_rxeof(adapter, adapter->rx_process_limit, NULL);
 		EM_TX_LOCK(adapter);
 		lem_txeof(adapter);
 		if (!IFQ_DRV_IS_EMPTY(&ifp->if_snd))
 			lem_start_locked(ifp);
 		EM_TX_UNLOCK(adapter);
+		if (more) {
+			taskqueue_enqueue(adapter->tq, &adapter->rxtx_task);
+			return;
+		}
 	}
 
 	if (ifp->if_drv_flags & IFF_DRV_RUNNING)
@@ -3269,8 +3281,6 @@ lem_setup_receive_structures(struct adapter *adapter)
  *  Enable receive unit.
  *
  **********************************************************************/
-#define MAX_INTS_PER_SEC	8000
-#define DEFAULT_ITR	     1000000000/(MAX_INTS_PER_SEC * 256)
 
 static void
 lem_initialize_receive_unit(struct adapter *adapter)
@@ -4596,6 +4606,8 @@ lem_sysctl_int_delay(SYSCTL_HANDLER_ARGS)
 		return (EINVAL);
 	info->value = usecs;
 	ticks = EM_USECS_TO_TICKS(usecs);
+	if (info->offset == E1000_ITR)	/* units are 256ns here */
+		ticks *= 4;
 
 	adapter = info->adapter;
 	
diff --git a/sys/dev/e1000/if_lem.h b/sys/dev/e1000/if_lem.h
index c1973e5..235277d 100644
--- a/sys/dev/e1000/if_lem.h
+++ b/sys/dev/e1000/if_lem.h
@@ -363,6 +363,7 @@ struct adapter {
 	struct em_int_delay_info tx_abs_int_delay;
 	struct em_int_delay_info rx_int_delay;
 	struct em_int_delay_info rx_abs_int_delay;
+	struct em_int_delay_info tx_itr;
 
 	/*
 	 * Transmit definitions