[ovs-dev] [PATCH V2 11/19] dpif-netdev: Read hw stats during flow_dump_next() call

[Eli Britstein]

On 12/4/2019 5:16 PM, Ilya Maximets wrote:
> On 02.12.2019 09:41, Eli Britstein wrote:
>> From: Ophir Munk <ophirmu at mellanox.com>
>>
>> Use netdev dump flow next API in order to update the statistics of fully
>> offloaded flows.
>>
>> Co-authored-by: Eli Britstein <elibr at mellanox.com>
>> Signed-off-by: Ophir Munk <ophirmu at mellanox.com>
>> Reviewed-by: Oz Shlomo <ozsh at mellanox.com>
>> Signed-off-by: Eli Britstein <elibr at mellanox.com>
>> ---
>>   lib/dpif-netdev.c | 42 ++++++++++++++++++++++++++++++++++++++++--
>>   1 file changed, 40 insertions(+), 2 deletions(-)
>>
>> diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
>> index 5142bad1d..bfeb1e7b0 100644
>> --- a/lib/dpif-netdev.c
>> +++ b/lib/dpif-netdev.c
>> @@ -527,6 +527,7 @@ struct dp_netdev_flow {
>>   
>>       bool dead;
>>       uint32_t mark;               /* Unique flow mark assigned to a flow */
>> +    bool actions_offloaded;      /* true if flow is fully offloaded */
>>   
>>       /* Statistics. */
>>       struct dp_netdev_flow_stats stats;
>> @@ -2410,6 +2411,7 @@ dp_netdev_flow_offload_put(struct dp_flow_offload_item *offload)
>>           }
>>       }
>>       info.flow_mark = mark;
>> +    info.actions_offloaded = &flow->actions_offloaded;
>>   
>>       ovs_mutex_lock(&pmd->dp->port_mutex);
>>       port = dp_netdev_lookup_port(pmd->dp, in_port);
>> @@ -3073,8 +3075,8 @@ dp_netdev_flow_to_dpif_flow(const struct dp_netdev_flow *netdev_flow,
>>       flow->pmd_id = netdev_flow->pmd_id;
>>       get_dpif_flow_stats(netdev_flow, &flow->stats);
>>   
>> -    flow->attrs.offloaded = false;
>> -    flow->attrs.dp_layer = "ovs";
>> +    flow->attrs.offloaded = netdev_flow->actions_offloaded;
>> +    flow->attrs.dp_layer = flow->attrs.offloaded ? "in_hw" : "ovs";
>>   }
>>   
>>   static int
>> @@ -3244,6 +3246,7 @@ dp_netdev_flow_add(struct dp_netdev_pmd_thread *pmd,
>>       flow->dead = false;
>>       flow->batch = NULL;
>>       flow->mark = INVALID_FLOW_MARK;
>> +    flow->actions_offloaded = false;
>>       *CONST_CAST(unsigned *, &flow->pmd_id) = pmd->core_id;
>>       *CONST_CAST(struct flow *, &flow->flow) = match->flow;
>>       *CONST_CAST(ovs_u128 *, &flow->ufid) = *ufid;
>> @@ -3598,6 +3601,37 @@ dpif_netdev_flow_dump_thread_destroy(struct dpif_flow_dump_thread *thread_)
>>       free(thread);
>>   }
>>   
>> +static int
>> +dpif_netdev_offload_used(struct dp_netdev_flow *netdev_flow,
>> +                         struct dp_netdev_pmd_thread *pmd)
>> +{
>> +    struct netdev_flow_dump netdev_dump;
>> +    struct dpif_flow_stats stats;
>> +    ovs_u128 ufid;
>> +    bool has_next;
>> +
>> +    netdev_dump.port = netdev_flow->flow.in_port.odp_port;
>> +    netdev_dump.netdev = netdev_ports_get(netdev_dump.port, pmd->dp->class);
>> +    if (!netdev_dump.netdev) {
>> +        return -1;
>> +    }
>> +    /* get offloaded stats */
>> +    ufid = netdev_flow->mega_ufid;
>> +    has_next = netdev_flow_dump_next(&netdev_dump, NULL, NULL, &stats, NULL,
>> +                                     &ufid, NULL, NULL);
>
> This will not work with linux TC flow API.
> You should not create 'netdev_flow_dump' by yourself, it must be created
> by the netdev_ports_flow_dump_create().

It is different in linux TC.

In kernel, dump request is done in dump_create API, for each device 
(using netdev_ports_flow_dump_create).

In user space we don't query the driver at all but the flows are looped 
by their PMD. We don't need any specific netdev action.

In kernel, dump next handle a chunk of replies from the kernel, without 
any known order or properties - neither by device nor by any other 
property, and the next handles the multi-threaded aspect of the dump.

In user space the flows are known by the PMD looping, and the 
multi-threaded scheme is handled by the PMD thread, so this is also 
different.

In kernel, the dump_next gets the flows from the kernel, and deduct the 
UFID for each one. In user space we get the UFID as known, and deduct 
the rte_flow, also different.

The code in this commit is not relevant for linux TC, not breaking it, 
so I don't see "this will will not work with linux TC" issue.

>
> Best regards, Ilya Maximets.