[dpdk-dev] [PATCH] examples/bond: wait for slaves to become active

[Radu Nicolau]

On 11/28/2018 2:28 PM, Chas Williams wrote:
>
>
> On 11/28/2018 08:48 AM, Radu Nicolau wrote:
>> Hi
>>
>>
>> On 11/28/2018 11:08 AM, Ferruh Yigit wrote:
>>> On 11/14/2018 12:19 PM, Radu Nicolau wrote:
>>>> Do not start the packet processing threads until all configured
>>>> slaves become active.
>>> Hi Radu,
>>>
>>> What happens if packet processing threads started before all slaves 
>>> active? Exit
>>> app, error, crash?
>>>
>>> So can we say this patch is fixing packet forwarding? (fix in title?)
>>>
>>> And do we know what break it, why this was not required previously 
>>> but required
>>> now? (Fixes line ?)
>>  From what I see, the problem was always there: bond_ethdev_rx_burst 
>> will cycle through slaves, but if called more times with no active 
>> slaves the active slave index will point out of bounds, resulting in 
>> a segfault.
>> While this may require a better fix, this patch is an improvement 
>> even if that fix comes - the configured slaves needs to be checked, 
>> and if none became active there is no point going further.
>>
>> in bond_ethdev_rx_burst:
>>
>> slave_count = internals->active_slave_count;
>> ...
>>      if (++internals->active_slave == slave_count)
>>          internals->active_slave = 0;
>> slave_count is zero, the if() will never be true and active_slave 
>> will be continuously incremented. It was not written to work with no 
>> active slaves.
>
> Just create another patch for the rx routines.  If the active_slave_count
> is 0, there's nothing to do really.  It should just return and not
> bother with any of the other work.
I can do that, and it will be the better fix I mentioned.
But I still think this patch makes the sample app better, at least it 
gives a hint to someone looking to develop its own app to check on the 
slaves' status before proceeding to rx.
>
>>
>>>
>>> Thanks,
>>> ferruh
>>>
>>>> Signed-off-by: Radu Nicolau <radu.nicolau at intel.com>
>>>> ---
>>>>   examples/bond/main.c | 15 +++++++++++++++
>>>>   1 file changed, 15 insertions(+)
>>>>
>>>> diff --git a/examples/bond/main.c b/examples/bond/main.c
>>>> index b282e68..6623cae 100644
>>>> --- a/examples/bond/main.c
>>>> +++ b/examples/bond/main.c
>>>> @@ -220,6 +220,7 @@ bond_port_init(struct rte_mempool *mbuf_pool)
>>>>       struct rte_eth_rxconf rxq_conf;
>>>>       struct rte_eth_txconf txq_conf;
>>>>       struct rte_eth_conf local_port_conf = port_conf;
>>>> +    uint16_t wait_counter = 20;
>>>>       retval = rte_eth_bond_create("net_bonding0", BONDING_MODE_ALB,
>>>>               0 /*SOCKET_ID_ANY*/);
>>>> @@ -274,6 +275,20 @@ bond_port_init(struct rte_mempool *mbuf_pool)
>>>>       if (retval < 0)
>>>>           rte_exit(retval, "Start port %d failed (res=%d)", 
>>>> BOND_PORT, retval);
>>>> +    printf("Waiting for slaves to become active...");
>>>> +    while (wait_counter) {
>>>> +        uint16_t act_slaves[16] = {0};
>>>> +        if (rte_eth_bond_active_slaves_get(BOND_PORT, act_slaves, 
>>>> 16) ==
>>>> +                slaves_count) {
>>>> +            printf("\n");
>>>> +            break;
>>>> +        }
>>>> +        sleep(1);
>>>> +        printf("...");
>>>> +        if (--wait_counter == 0)
>>>> +            rte_exit(-1, "\nFailed to activate slaves\n");
>>>> +    }
>>>> +
>>>>       rte_eth_promiscuous_enable(BOND_PORT);
>>>>       struct ether_addr addr;
>>>>
>>