On 3/18/2019 1:37 AM, Lu, Wenzhuo wrote:
> Hi Ferruh,
>
>
>> -----Original Message-----
>> From: Yigit, Ferruh
>> Sent: Saturday, March 16, 2019 1:54 AM
>> To: Lu, Wenzhuo <wenzhuo...@intel.com>; dev@dpdk.org
>> Subject: Re: [dpdk-dev] [PATCH v3 6/8] net/ice: support Rx AVX2 vector
>>
>> On 3/15/2019 6:22 AM, Wenzhuo Lu wrote:
>>> Signed-off-by: Wenzhuo Lu <wenzhuo...@intel.com>
>> <...>
>>
>>> +#ifdef RTE_LIBRTE_ICE_16BYTE_RX_DESC
>>> + /* for AVX we need alignment otherwise loads are not
>> atomic */
>>> + if (avx_aligned) {
>>> + /* load in descriptors, 2 at a time, in reverse order */
>>> + raw_desc6_7 = _mm256_load_si256((void *)(rxdp +
>> 6));
>>> + rte_compiler_barrier();
>>> + raw_desc4_5 = _mm256_load_si256((void *)(rxdp +
>> 4));
>>> + rte_compiler_barrier();
>>> + raw_desc2_3 = _mm256_load_si256((void *)(rxdp +
>> 2));
>>> + rte_compiler_barrier();
>>> + raw_desc0_1 = _mm256_load_si256((void *)(rxdp +
>> 0));
>>> + } else
>>> +#endif
>>> + do {
>>> + const __m128i raw_desc7 =
>>> + _mm_load_si128((void *)(rxdp + 7));
>>> + rte_compiler_barrier();
>>> + const __m128i raw_desc6 =
>>> + _mm_load_si128((void *)(rxdp + 6));
>>> + rte_compiler_barrier();
>>> + const __m128i raw_desc5 =
>>> + _mm_load_si128((void *)(rxdp + 5));
>>> + rte_compiler_barrier();
>>> + const __m128i raw_desc4 =
>>> + _mm_load_si128((void *)(rxdp + 4));
>>> + rte_compiler_barrier();
>>> + const __m128i raw_desc3 =
>>> + _mm_load_si128((void *)(rxdp + 3));
>>> + rte_compiler_barrier();
>>> + const __m128i raw_desc2 =
>>> + _mm_load_si128((void *)(rxdp + 2));
>>> + rte_compiler_barrier();
>>> + const __m128i raw_desc1 =
>>> + _mm_load_si128((void *)(rxdp + 1));
>>> + rte_compiler_barrier();
>>> + const __m128i raw_desc0 =
>>> + _mm_load_si128((void *)(rxdp + 0));
>>> +
>>> + raw_desc6_7 =
>>> + _mm256_inserti128_si256
>>> +
>> (_mm256_castsi128_si256(raw_desc6),
>>> + raw_desc7, 1);
>>> + raw_desc4_5 =
>>> + _mm256_inserti128_si256
>>> +
>> (_mm256_castsi128_si256(raw_desc4),
>>> + raw_desc5, 1);
>>> + raw_desc2_3 =
>>> + _mm256_inserti128_si256
>>> +
>> (_mm256_castsi128_si256(raw_desc2),
>>> + raw_desc3, 1);
>>> + raw_desc0_1 =
>>> + _mm256_inserti128_si256
>>> +
>> (_mm256_castsi128_si256(raw_desc0),
>>> + raw_desc1, 1);
>>> + } while (0);
>>
>> Is this to provide the proper indention because of the above #ifdef block? If
>> so why not simple { } for the scope, is do{ }while(0) has benefit against it?
> Yes, it's for the indention. To my opinion, "do while" looks friendly to the
> readers as we always use it in the macros. Only "{}" looks missing a function
> name or a "for ()" :)
>
I found '{ }' more clear but no strong opinion, perhaps a comment to clarify to
intention can be good but that also looks like optional, so up to you.
