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[ovs-dev] netdev-dpdk: Add Flow Control support.

Message ID 2EF2F5C0CC56984AA024D0B180335FCB13E0CBB9@IRSMSX102.ger.corp.intel.com
State Accepted
Headers show

Commit Message

Chandran, Sugesh July 28, 2016, 9:11 a.m. UTC 
Hi Bhanu and Daniele,
Thank you for your time to review the patch,

Please find my answers inline prefix with [Sugesh]

Regards
_Sugesh

From: Daniele Di Proietto [mailto:diproiettod@ovn.org]

Sent: Thursday, July 28, 2016 1:38 AM
To: Chandran, Sugesh <sugesh.chandran@intel.com>; Bodireddy, Bhanuprakash <bhanuprakash.bodireddy@intel.com>
Cc: dev@openvswitch.org
Subject: Re: [ovs-dev] [PATCH] netdev-dpdk: Add Flow Control support.

Thanks for the patch.
I agree, I'd be nice to document this in INSTALL.DPDK-ADVANCED.md<http://INSTALL.DPDK-ADVANCED.md>
[Sugesh] Agreed, Will add that.
We should also document the new fields in vswitchd/vswitch.xml.
[Sugesh] Will do
Probably it's better to use "true" and "false" rather that "on" and "off", for consistency with other configuration options and so that we can use smap_get_bool().
[Sugesh] Will update it.
I assume it's ok to call rte_eth_dev_flow_ctrl_get()/_set() while the device is transmitting/receiving.
[Sugesh], yes, it’s a run time parameter.
Maybe it would be better to cache fc_conf in struct netdev_dpdk and call _set() only if we have to make a change?
[Sugesh] : Will add it in the ‘netdev_dpdk’.

2016-07-22 6:18 GMT-07:00 Sugesh Chandran <sugesh.chandran@intel.com<mailto:sugesh.chandran@intel.com>>:
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=on'

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

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

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=on'

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

Signed-off-by: Sugesh Chandran <sugesh.chandran@intel.com<mailto:sugesh.chandran@intel.com>>

---
 lib/netdev-dpdk.c | 68 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 68 insertions(+)

+                          OVS_REQUIRES(dev->mutex)

Minor: the other thread safety annotations are not aligned with the parameters, but are just indented four spaces.
[Sugesh] Will correct it.

+{
+    if (rte_eth_dev_flow_ctrl_set(dev->port_id, fc_conf) != 0) {

I'd drop the != 0

+        VLOG_ERR("Failed to enable flow control on device %d", dev->port_id);

VLOG_WARN is probably enough
[Sugesh] Ok.

+    }
+}

 static int
 dpdk_eth_dev_init(struct netdev_dpdk *dev) OVS_REQUIRES(dpdk_mutex)
@@ -991,6 +1052,13 @@ 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) {
+        struct rte_eth_fc_conf fc_conf = {0};
+        dpdk_eth_parse_flow_ctrl(dev, args, &fc_conf);

I think it'd be better to extract the fields from 'args' here and pass them to dpdk_eth_parse_flow_ctrl(), which would probably need a new name, but that's just my preference.
[Sugesh] : Looks fine for me, Will extract the fields here and change the function to dpdk_eth_flow_ctrl_setup()

+        dpdk_eth_flow_ctrl_config(dev, &fc_conf);
+    }
     ovs_mutex_unlock(&dev->mutex);

     return 0;
--
2.5.0

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[Sugesh] : I will release v2 patch after incorporating the comments.
diff mbox

Patch

diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
index 85b18fd..74efd25 100644
--- a/lib/netdev-dpdk.c
+++ b/lib/netdev-dpdk.c
@@ -634,6 +634,67 @@  dpdk_eth_dev_queue_setup(struct netdev_dpdk *dev, int n_rxq, int n_txq)
     return diag;
 }

+static void
+dpdk_eth_parse_flow_ctrl(struct netdev_dpdk *dev,
+                         const struct smap *args,
+                         struct rte_eth_fc_conf *fc_conf)
+                         OVS_REQUIRES(dev->mutex)

Minor: the other thread safety annotations are not aligned with the parameters, but are just indented four spaces.
[Sugesh] Sorry, Will correct it.

+{
+    int ret = 0;
+    int rx_fc_en = 0;
+    int tx_fc_en = 0;
+    const char *rx_flow_mode;
+    const char *tx_flow_mode;
+    const char *flow_autoneg;
+    enum rte_eth_fc_mode fc_mode_set[2][2] = {{RTE_FC_NONE, RTE_FC_TX_PAUSE},
+                                              {RTE_FC_RX_PAUSE, RTE_FC_FULL}
+                                             };
+
+    ret = rte_eth_dev_flow_ctrl_get(dev->port_id, fc_conf);
+    if (ret != 0) {
+        VLOG_DBG("cannot get flow control parameters on port=%d, err=%s",
+                 dev->port_id, rte_strerror(ret));

I'm not sure, do we need to change 'ret' sign before passing it to rte_strerror()?
[Sugesh] : Either I can change it to rte_strerror(abs(ret)), or print the error code as is.
All the existing ‘flow_ctrl_get’ driver implementation doesn’t return any error code in DPDK. It returns ‘0’ always. So I think its OK to just print the error code as it is. What do you think?

+        return;
+    }
+    rx_flow_mode = smap_get(args, "rx-flow-ctrl");
+    tx_flow_mode = smap_get(args, "tx-flow-ctrl");
+    flow_autoneg = smap_get(args, "flow-ctrl-autoneg");
+    if (rx_flow_mode) {
+        if (!strcmp(rx_flow_mode, "on")) {
+            rx_fc_en = 1;
+        }
+        else if (!strcmp(rx_flow_mode, "off")) {
+            rx_fc_en = 0;
+        }
+    }
+    if (tx_flow_mode) {
+        if (!strcmp(tx_flow_mode, "on")) {
+            tx_fc_en =1;
+        }
+        else if (!strcmp(tx_flow_mode, "off")) {
+            tx_fc_en =0;
+        }
+    }
+    if (flow_autoneg) {
+        if (!strcmp(flow_autoneg, "on")) {
+            fc_conf->autoneg = 1;
+        }
+        else if (!strcmp(flow_autoneg, "off")) {
+            fc_conf->autoneg = 0;
+        }
+    }
+    fc_conf->mode = fc_mode_set[tx_fc_en][rx_fc_en];
+}
+
+static void
+dpdk_eth_flow_ctrl_config(struct netdev_dpdk *dev,
+                          struct rte_eth_fc_conf *fc_conf)