Re: [PATCH v1] net/i40e: remove redundant number of packets check

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 3/4/2022 1:23 AM, Zhang, Qi Z wrote:
> 
> 
>> -----Original Message-----
>> From: Yigit, Ferruh <ferruh.yigit@intel.com>
>> Sent: Friday, March 4, 2022 12:44 AM
>> To: Zhang, Qi Z <qi.z.zhang@intel.com>; Feifei Wang <feifei.wang2@arm.com>;
>> Xing, Beilei <beilei.xing@intel.com>; David Christensen
>> <drc@linux.vnet.ibm.com>; Richardson, Bruce <bruce.richardson@intel.com>;
>> Ananyev, Konstantin <konstantin.ananyev@intel.com>; Ruifeng Wang
>> <ruifeng.wang@arm.com>
>> Cc: dev@dpdk.org; nd@arm.com; Honnappa Nagarahalli
>> <honnappa.nagarahalli@arm.com>; Thomas Monjalon
>> <thomas@monjalon.net>; David Marchand <david.marchand@redhat.com>
>> Subject: Re: [PATCH v1] net/i40e: remove redundant number of packets check
>>
>> On 3/3/2022 2:28 AM, Zhang, Qi Z wrote:
>>>
>>>
>>>> -----Original Message-----
>>>> From: Feifei Wang <feifei.wang2@arm.com>
>>>> Sent: Thursday, March 3, 2022 9:54 AM
>>>> To: Xing, Beilei <beilei.xing@intel.com>; David Christensen
>>>> <drc@linux.vnet.ibm.com>; Richardson, Bruce
>>>> <bruce.richardson@intel.com>; Ananyev, Konstantin
>>>> <konstantin.ananyev@intel.com>; Ruifeng Wang <ruifeng.wang@arm.com>
>>>> Cc: dev@dpdk.org; nd@arm.com; Feifei Wang <feifei.wang2@arm.com>;
>>>> Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
>>>> Subject: [PATCH v1] net/i40e: remove redundant number of packets
>>>> check
>>>>
>>>> For i40e_xmit_pkts_vec_xx function, it checks nb_pkts to ensure
>>>> nb_pkts does not cross rs_thresh.
>>>>
>>>> However, in i40e_xmit_fixed_burst_vec_xx function, this check will be
>>>> performed again. To improve code, delete this redundant check.
>>>>
>>>> Suggested-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
>>>> Signed-off-by: Feifei Wang <feifei.wang2@arm.com>
>>>> Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
>>>
>>> Applied to dpdk-next-net-intel.
>>>
>>
>> Hi Qi,
>>
>> This patch is not acked by the i40e maintainers.
>>
>> And this is changing the datapath for the -rc3, two weeks before the release. Is
>> it tested enough?
>>
>> What is the gain with this patch, I don't see any numbers in the commit log.
>> If the gain is small, can we postpone this patch to next release instead of getting
>> it for -rc3?
> 
> The patch applied the same thing as below which I have reviewed.
> https://patchwork.dpdk.org/project/dpdk/patch/20220222224818.8612-1-kathleen.capella@arm.com/
> 
> I didn't see the risk of having it, and I will add a "reviewed-by" to avoid confusion, but if you think it's risky, we can still defer it to next-net.
> 

Code change looks simple, but risk is more theoretical
to get a datapath code optimization close to the release,
and Feifei reported that there is no visible performance
gain.
So I think safer to postpone to next release if you don't
object.