MFC r289238

Add support for sysctl knobs to live tune the per interrupt rx/tx packet
processing limits in ixgbe(4)

Submitted by:	jason wolfe (j-nitrology.com)
Sponsored by:	Limelight Networks

1 files changed, 21 insertions, 5 deletions

diff --git a/sys/dev/ixgbe/if_ixv.c b/sys/dev/ixgbe/if_ixv.c
index a550a85..bd6b0ed 100644
--- a/sys/dev/ixgbe/if_ixv.c
+++ b/sys/dev/ixgbe/if_ixv.c
@@ -115,6 +115,8 @@ static void	ixv_save_stats(struct adapter *);
 static void	ixv_init_stats(struct adapter *);
 static void	ixv_update_stats(struct adapter *);
 static void	ixv_add_stats_sysctls(struct adapter *);
+static void	ixv_set_sysctl_value(struct adapter *, const char *,
+		    const char *, int *, int);
 
 /* The MSI/X Interrupt handlers */
 static void	ixv_msix_que(void *);
@@ -301,6 +303,15 @@ ixv_attach(device_t dev)
 		goto err_out;
 	}
 
+	/* Sysctls for limiting the amount of work done in the taskqueues */
+	ixv_set_sysctl_value(adapter, "rx_processing_limit",
+	    "max number of rx packets to process",
+	    &adapter->rx_process_limit, ixv_rx_process_limit);
+
+	ixv_set_sysctl_value(adapter, "tx_processing_limit",
+	    "max number of tx packets to process",
+	    &adapter->tx_process_limit, ixv_tx_process_limit);
+
 	/* Do descriptor calc and sanity checks */
 	if (((ixv_txd * sizeof(union ixgbe_adv_tx_desc)) % DBA_ALIGN) != 0 ||
 	    ixv_txd < MIN_TXD || ixv_txd > MAX_TXD) {
@@ -1555,9 +1566,6 @@ ixv_initialize_transmit_units(struct adapter *adapter)
 		/* Set Tx Tail register */
 		txr->tail = IXGBE_VFTDT(i);
 
-		/* Set the processing limit */
-		txr->process_limit = ixv_tx_process_limit;
-
 		/* Set Ring parameters */
 		IXGBE_WRITE_REG(hw, IXGBE_VFTDBAL(i),
 		       (tdba & 0x00000000ffffffffULL));
@@ -1637,8 +1645,6 @@ ixv_initialize_receive_units(struct adapter *adapter)
 		IXGBE_WRITE_REG(hw, IXGBE_VFRDH(rxr->me), 0);
 		IXGBE_WRITE_REG(hw, IXGBE_VFRDT(rxr->me),
 		    adapter->num_rx_desc - 1);
-		/* Set the processing limit */
-		rxr->process_limit = ixv_rx_process_limit;
 
 		/* Set Rx Tail register */
 		rxr->tail = IXGBE_VFRDT(rxr->me);
@@ -2041,6 +2047,16 @@ ixv_add_stats_sysctls(struct adapter *adapter)
 			"# of times not enough descriptors were available during TX");
 }
 
+static void
+ixv_set_sysctl_value(struct adapter *adapter, const char *name,
+	const char *description, int *limit, int value)
+{
+	*limit = value;
+	SYSCTL_ADD_INT(device_get_sysctl_ctx(adapter->dev),
+	    SYSCTL_CHILDREN(device_get_sysctl_tree(adapter->dev)),
+	    OID_AUTO, name, CTLFLAG_RW, limit, value, description);
+}
+
 /**********************************************************************
  *
  *  This routine is called only when em_display_debug_stats is enabled.