netdev-dpdk: Add Flow Control support.

Add support for flow-control(mac control frame) to DPDK enabled physical
port types. By default, the flow-control is OFF on both rx and tx side.
The flow control can be enabled/disabled either when adding a port to OVS
or at run time.

For eg:
To enable flow control support at tx side while adding a port, add the
'tx-flow-ctrl' option to the 'ovs-vsctl add-port' command-line as below.

 'ovs-vsctl add-port br0 dpdk0 -- \
  set Interface dpdk0 type=dpdk options:tx-flow-ctrl=true'

Similarly to enable rx flow control,
 'ovs-vsctl add-port br0 dpdk0 -- \
  set Interface dpdk0 type=dpdk options:rx-flow-ctrl=true'

And to enable the flow control auto-negotiation,
 'ovs-vsctl add-port br0 dpdk0 -- \
  set Interface dpdk0 type=dpdk options:flow-ctrl-autoneg=true'

To turn ON the tx flow control at run time(After the port is being added
to OVS), the command-line input will be,
 'ovs-vsctl set Interface dpdk0 options:tx-flow-ctrl=true'

The flow control parameters can be turned off by setting 'false' to the
respective parameter. To dsiable the flow control at tx side,
 'ovs-vsctl set Interface dpdk0 options:tx-flow-ctrl=false'

Signed-off-by: Sugesh Chandran <sugesh.chandran@intel.com>
Acked-by: Bhanuprakash Bodireddy <Bhanuprakash.bodireddy@intel.com>
Signed-off-by: Daniele Di Proietto <diproiettod@vmware.com>

AUTHORS

@@ -225,6 +225,7 @@ Sten Spans              sten@blinkenlights.nl
 Stephane A. Sezer       sas@cd80.net
 Stephen Finucane        stephen.finucane@intel.com
 Steve Ruan              ruansx@cn.ibm.com
+Sugesh Chandran         sugesh.chandran@intel.com
 SUGYO Kazushi           sugyo.org@gmail.com
 Tadaaki Nagao           nagao@stratosphere.co.jp
 Terry Wilson            twilson@redhat.com

INSTALL.DPDK-ADVANCED.md

@@ -11,7 +11,8 @@ OVS DPDK ADVANCED INSTALL GUIDE
 6. [Vhost Walkthrough](#vhost)
 7. [QOS](#qos)
 8. [Rate Limiting](#rl)
-9. [Vsperf](#vsperf)
+9. [Flow Control](#fc)
+10. [Vsperf](#vsperf)
 
 ## <a name="overview"></a> 1. Overview
 
@@ -827,7 +828,41 @@ To clear the ingress policer configuration from the port use the following:
 
 For more details regarding ingress-policer see the vswitch.xml.
 
-## <a name="vsperf"></a> 9. Vsperf
+## <a name="fc"></a> 9. Flow control.
+Flow control can be enabled only on DPDK physical ports.
+To enable flow control support at tx side while adding a port, add the
+'tx-flow-ctrl' option to the 'ovs-vsctl add-port' as in the eg: below.
+
+```
+ovs-vsctl add-port br0 dpdk0 -- \
+set Interface dpdk0 type=dpdk options:tx-flow-ctrl=true
+```
+
+Similarly to enable rx flow control,
+
+```
+ovs-vsctl add-port br0 dpdk0 -- \
+set Interface dpdk0 type=dpdk options:rx-flow-ctrl=true
+```
+
+And to enable the flow control auto-negotiation,
+
+```
+ovs-vsctl add-port br0 dpdk0 -- \
+set Interface dpdk0 type=dpdk options:flow-ctrl-autoneg=true
+```
+
+To turn ON the tx flow control at run time(After the port is being added
+to OVS), the command-line input will be,
+
+`ovs-vsctl set Interface dpdk0 options:tx-flow-ctrl=true`
+
+The flow control parameters can be turned off by setting 'false' to the
+respective parameter. To disable the flow control at tx side,
+
+`ovs-vsctl set Interface dpdk0 options:tx-flow-ctrl=false`
+
+## <a name="vsperf"></a> 10. Vsperf
 
 Vsperf project goal is to develop vSwitch test framework that can be used to
 validate the suitability of different vSwitch implementations in a Telco deployment

lib/netdev-dpdk.c

@@ -375,6 +375,9 @@ struct netdev_dpdk {
     OVSRCU_TYPE(struct ingress_policer *) ingress_policer;
     uint32_t policer_rate;
     uint32_t policer_burst;
+
+    /* DPDK-ETH Flow control */
+    struct rte_eth_fc_conf fc_conf;
 };
 
 struct netdev_rxq_dpdk {
@@ -628,6 +631,13 @@ dpdk_eth_dev_queue_setup(struct netdev_dpdk *dev, int n_rxq, int n_txq)
     return diag;
 }
 
+static void
+dpdk_eth_flow_ctrl_setup(struct netdev_dpdk *dev) OVS_REQUIRES(dev->mutex)
+{
+    if (rte_eth_dev_flow_ctrl_set(dev->port_id, &dev->fc_conf)) {
+        VLOG_WARN("Failed to enable flow control on device %d", dev->port_id);
+    }
+}
 
 static int
 dpdk_eth_dev_init(struct netdev_dpdk *dev) OVS_REQUIRES(dpdk_mutex)
@@ -676,6 +686,14 @@ dpdk_eth_dev_init(struct netdev_dpdk *dev) OVS_REQUIRES(dpdk_mutex)
     dev->buf_size = mbp_priv->mbuf_data_room_size - RTE_PKTMBUF_HEADROOM;
 
     dev->flags = NETDEV_UP | NETDEV_PROMISC;
+
+    /* Get the Flow control configuration for DPDK-ETH */
+    diag = rte_eth_dev_flow_ctrl_get(dev->port_id, &dev->fc_conf);
+    if (diag) {
+        VLOG_DBG("cannot get flow control parameters on port=%d, err=%d",
+                 dev->port_id, diag);
+    }
+
     return 0;
 }
 
@@ -765,6 +783,8 @@ netdev_dpdk_init(struct netdev *netdev, unsigned int port_no,
     dev->requested_n_rxq = netdev->n_rxq;
     dev->requested_n_txq = netdev->n_txq;
 
+    /* Initialize the flow control to NULL */
+    memset(&dev->fc_conf, 0, sizeof dev->fc_conf);
     if (type == DPDK_DEV_ETH) {
         err = dpdk_eth_dev_init(dev);
         if (err) {
@@ -983,6 +1003,22 @@ netdev_dpdk_set_config(struct netdev *netdev, const struct smap *args)
         dev->requested_n_rxq = new_n_rxq;
         netdev_request_reconfigure(netdev);
     }
+
+    /* Flow control configuration for DPDK Ethernet ports. */
+    if (dev->type == DPDK_DEV_ETH) {
+        bool rx_fc_en = false;
+        bool tx_fc_en = false;
+        enum rte_eth_fc_mode fc_mode_set[2][2] =
+                                           {{RTE_FC_NONE, RTE_FC_TX_PAUSE},
+                                            {RTE_FC_RX_PAUSE, RTE_FC_FULL}
+                                           };
+        rx_fc_en = smap_get_bool(args, "rx-flow-ctrl", false);
+        tx_fc_en = smap_get_bool(args, "tx-flow-ctrl", false);
+        dev->fc_conf.autoneg = smap_get_bool(args, "flow-ctrl-autoneg", false);
+        dev->fc_conf.mode = fc_mode_set[tx_fc_en][rx_fc_en];
+
+        dpdk_eth_flow_ctrl_setup(dev);
+    }
     ovs_mutex_unlock(&dev->mutex);
 
     return 0;

vswitchd/vswitch.xml

@@ -3146,6 +3146,30 @@
       </column>
     </group>
 
+    <group title="Flow control Configuration">
+      <p>
+        Ethernet flow control defined in IEEE 802.1Qbb provides link level flow
+        control using MAC pause frames.  Implemented only for interfaces with
+        type <code>dpdk</code>.
+      </p>
+
+      <column name="options" key="rx-flow-ctrl" type='{"type": "boolean"}'>
+        Set to <code>true</code> to enable Rx flow control on physical ports.
+        By default, Rx flow control is disabled.
+      </column>
+
+      <column name="options" key="tx-flow-ctrl" type='{"type": "boolean"}'>
+        Set to <code>true</code> to enable Tx flow control on physical ports.
+        By default, Tx flow control is disabled.
+      </column>
+
+      <column name="options" key="flow-ctrl-autoneg"
+              type='{"type": "boolean"}'>
+        Set to <code>true</code> to enable flow control auto negotiation on
+        physical ports. By default, auto-neg is disabled.
+      </column>
+    </group>
+
     <group title="Common Columns">
       The overall purpose of these columns is described under <code>Common
       Columns</code> at the beginning of this document.