[ovs-dev] [PATCH] netdev-dpdk: Fix failure to configure flow control at netdev-init.

[Ian Stokes]

On 7/13/2018 6:13 PM, Ian Stokes wrote:
> On 7/10/2018 2:23 PM, Sugesh Chandran wrote:
>> Configuring flow control at ixgbe netdev-init is throwing error in port
>> start.
>>
>> For eg: without this fix, user cannot configure flow control on ixgbe 
>> dpdk
>> port as below,
>>
>> "
>>      ovs-vsctl add-port br0 dpdk0 -- set Interface dpdk0 type=dpdk \
>>          options:dpdk-devargs=0000:05:00.1 options:rx-flow-ctrl=true
>> "
>>
>> Instead,  it must be configured as two different commands,
>>
>> "
>>      ovs-vsctl add-port br0 dpdk0 -- set Interface dpdk0 type=dpdk \
>>                 options:dpdk-devargs=0000:05:00.1
>>      ovs-vsctl set Interface dpdk0 options:rx-flow-ctrl=true
>> "
>>
>> The DPDK ixgbe driver is now validating all the 'rte_eth_fc_conf' 
>> fields before
>> trying to configuring the dpdk ethdev. Hence OVS can no longer set the
>> 'dont care' fields to just '0' as before. This commit make sure all the
>> 'rte_eth_fc_conf' fields are populated with default values before the dev
>> init.
>>
> 
> Thanks for the patch Sugesh, I've applied to dpdk_merge and it will be 
> part of this weeks pull request.
> 
> I assume it should be backported to OVS 2.9 at least, do you know if it 
> should go to 2.8/2.7 also?

Hi Sugesh,

during further testing I found this breaks functionality for Virtual 
functions with OVS (specifically tested with igb_vf, i40e_vf and ixgbe_vf).

The port itself will fail to initialize with the following error:

netdev_dpdk|INFO|cannot get flow control parameters on port 2, err=-95

And is not added. as such I think flow control should only be optional 
as there is no guarantee it will be available for a given dpdk device 
and if unavailable it should not stop the port from being initialized.

I've pulled this patch from the merge request for master, I think the 
branch patches will have to be reworked also.

Ian
> 
> Ian
>> Signed-off-by: Sugesh Chandran <sugesh.chandran at intel.com>
>> ---
>>   lib/netdev-dpdk.c | 15 +++++++--------
>>   1 file changed, 7 insertions(+), 8 deletions(-)
>>
>> diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
>> index bb4d60f26..023b80d3e 100644
>> --- a/lib/netdev-dpdk.c
>> +++ b/lib/netdev-dpdk.c
>> @@ -1065,14 +1065,6 @@ dpdk_eth_dev_init(struct netdev_dpdk *dev)
>>       mbp_priv = rte_mempool_get_priv(dev->dpdk_mp->mp);
>>       dev->buf_size = mbp_priv->mbuf_data_room_size - 
>> RTE_PKTMBUF_HEADROOM;
>> -
>> -    /* 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 
>> "DPDK_PORT_ID_FMT
>> -                 ", err=%d", dev->port_id, diag);
>> -    }
>> -
>>       return 0;
>>   }
>> @@ -1773,6 +1765,13 @@ netdev_dpdk_set_config(struct netdev *netdev, 
>> const struct smap *args,
>>       autoneg = smap_get_bool(args, "flow-ctrl-autoneg", false);
>>       fc_mode = fc_mode_set[tx_fc_en][rx_fc_en];
>> +    /* Get the Flow control configuration for DPDK-ETH */
>> +    err = rte_eth_dev_flow_ctrl_get(dev->port_id, &dev->fc_conf);
>> +    if (err) {
>> +        VLOG_INFO("cannot get flow control parameters on port 
>> "DPDK_PORT_ID_FMT
>> +                 ", err=%d", dev->port_id, err);
>> +    }
>> +
>>       if (dev->fc_conf.mode != fc_mode || autoneg != 
>> dev->fc_conf.autoneg) {
>>           dev->fc_conf.mode = fc_mode;
>>           dev->fc_conf.autoneg = autoneg;
>>
> 
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