[dpdk-dev] [dpdk-stable] [PATCH] net/i40e: fix packet count for PF

Ferruh Yigit ferruh.yigit at intel.com
Fri Sep 15 12:47:46 CEST 2017


On 9/15/2017 11:33 AM, Zhang, Qi Z wrote:
> Sorry for late reply
> 
>> -----Original Message-----
>> From: Yigit, Ferruh
>> Sent: Monday, August 21, 2017 8:43 PM
>> To: Zhang, Qi Z <qi.z.zhang at intel.com>; Wu, Jingjing <jingjing.wu at intel.com>
>> Cc: dev at dpdk.org; stable at dpdk.org
>> Subject: Re: [dpdk-stable] [PATCH] net/i40e: fix packet count for PF
>>
>> On 8/20/2017 9:05 PM, Qi Zhang wrote:
>>> Previously, for PF statistics we use VSI register for packet count but
>>> use port's register for packet bytes, that cause inconsistent
>>> situation of PF statistics when some VF is active,  since it will
>>> cover VF's packet bytes but not packet count.
>>> The patch will take port register for PF packet count back, but still
>>> exclude main vsi's discard packet count.
>>> Just like pervious fix, its still not perfect,(since RX packet number
>>> is over counted when there is VF discard packet) but seems it make the
>>> overall better).
>>
>> What does Linux do for stats calculation?
>> I believe it is good to be consistent with it.
> 
> Kernel driver is quite different on the stats calucation, I don't think this patch is going to cover this.
> It just try to fix the mismatch between rxbytes and rx_packets on PF.
> But your suggestion is considerable

Method can be different, but numbers should be same :)
Not for this patch, bur for long term, I think having exact stats
numbers as Linux should be the target, if this is not the case already.

> 
>>
>>>
>>> Fixes: 9aace75fc82e ("i40e: fix statistics")
>>> Cc: stable at dpdk.org
>>>
>>> Signed-off-by: Qi Zhang <qi.z.zhang at intel.com>
>>> ---
>>>  drivers/net/i40e/i40e_ethdev.c | 13 +++++++------
>>>  1 file changed, 7 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/drivers/net/i40e/i40e_ethdev.c
>>> b/drivers/net/i40e/i40e_ethdev.c index 5f26e24..63acbb8 100644
>>> --- a/drivers/net/i40e/i40e_ethdev.c
>>> +++ b/drivers/net/i40e/i40e_ethdev.c
>>> @@ -2664,13 +2664,14 @@ i40e_dev_stats_get(struct rte_eth_dev *dev,
>> struct rte_eth_stats *stats)
>>>  	/* call read registers - updates values, now write them to struct */
>>>  	i40e_read_stats_registers(pf, hw);
>>>
>>> -	stats->ipackets = pf->main_vsi->eth_stats.rx_unicast +
>>> -			pf->main_vsi->eth_stats.rx_multicast +
>>> -			pf->main_vsi->eth_stats.rx_broadcast -
>>> +	stats->ipackets = ns->eth.rx_unicast +
>>> +			ns->eth.rx_multicast +
>>> +			ns->eth.rx_broadcast -
>>> +			ns->eth.rx_discards -
>>>  			pf->main_vsi->eth_stats.rx_discards;
>>
>> Both port rx_discards and PF rx_discards excluded, is this intentional?
>> Won't this cause double exclusion of some rx_discards packets?
> 
> Yes, this is intentional, port rx_discard and VSI rx_discard counts on different part of total drop packets.
>>
>>> -	stats->opackets = pf->main_vsi->eth_stats.tx_unicast +
>>> -			pf->main_vsi->eth_stats.tx_multicast +
>>> -			pf->main_vsi->eth_stats.tx_broadcast;
>>> +	stats->opackets = ns->eth.tx_unicast +
>>> +			ns->eth.tx_multicast +
>>> +			ns->eth.tx_broadcast;
>>>  	stats->ibytes   = ns->eth.rx_bytes;
>>>  	stats->obytes   = ns->eth.tx_bytes;
>>>  	stats->oerrors  = ns->eth.tx_errors +
>>
> 
> Regards
> Qi
> 



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