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

Daniele Di Proietto diproiettod at ovn.org
Thu Jul 28 00:37:55 UTC 2016


Thanks for the patch.

I agree, I'd be nice to document this in INSTALL.DPDK-ADVANCED.md

We should also document the new fields in vswitchd/vswitch.xml.

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().

I assume it's ok to call rte_eth_dev_flow_ctrl_get()/_set() while the
device is transmitting/receiving.

Maybe it would be better to cache fc_conf in struct netdev_dpdk and call
_set() only if we have to make a change?

2016-07-22 6:18 GMT-07:00 Sugesh Chandran <sugesh.chandran at 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 at intel.com>
> ---
>  lib/netdev-dpdk.c | 68
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 68 insertions(+)
>
> 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.


> +{
> +    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()?


> +        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)
> +                          OVS_REQUIRES(dev->mutex)
>

Minor: the other thread safety annotations are not aligned with the
parameters, but are just indented four spaces.


> +{
> +    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


> +    }
> +}
>
>  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.


> +        dpdk_eth_flow_ctrl_config(dev, &fc_conf);
> +    }
>      ovs_mutex_unlock(&dev->mutex);
>
>      return 0;
> --
> 2.5.0
>
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