[dpdk-dev] [PATCH] net/iavf: fix performance drop

Ferruh Yigit ferruh.yigit at intel.com
Wed Apr 28 13:32:25 CEST 2021


On 4/27/2021 3:57 AM, Zhang, Qi Z wrote:
> 
> 
>> -----Original Message-----
>> From: Lu, Wenzhuo <wenzhuo.lu at intel.com>
>> Sent: 2021年4月27日 9:51
>> To: Zhang, Qi Z <qi.z.zhang at intel.com>; dev at dpdk.org
>> Subject: RE: [dpdk-dev] [PATCH] net/iavf: fix performance drop
>>
>>>> +use_sse = true;
>>>> +if ((rte_cpu_get_flag_enabled(RTE_CPUFLAG_AVX2) == 1 ||
>>>> +     rte_cpu_get_flag_enabled(RTE_CPUFLAG_AVX512F) == 1) &&
>>>> +    rte_vect_get_max_simd_bitwidth() >= RTE_VECT_SIMD_256)
>>>> +use_avx2 = true;
>>>
>>>
>>> Not sure if the right path will be selected when avx512 is not true,
>>> (CC_AVX512_SUPPORT is disable) while check_ret is
>>> IAVF_VECTOR_OFFLOAD_PATH?
>>>
>>> Currently we have
>>>
>>> if (!use_sse && !use_avx2 && !use_avx512) goto normal;
>>>
>>> Should we also add below check?
>>>
>>> if (!use_avx512 && check_ret == IAVF_VECTOR_OFFLOAD_PATH)
>>>    goto normal;
>> Not necessary. As explained in the commit log, AVX2 and SSE support the
>> offload features. The purpose of this patch is to let AVX2 be chosen when
>> offload needed and AVX512 disable.
> 
> OK, now I understand it, I will suggest to change the commit log.
> 
> From 
> AVX2 and SSE don't have the offload path.
> 
> To 
> AVX2 and SSE Tx path already support offloads but can't selected.
> 

Isn't this related to the _Rx_ path?

> If you agree, will apply above during change during patch merge.
> 



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