Re: [dpdk-dev] [PATCH v3 1/8] net/hns3: support runtime config to select IO burst func

["Min Hu (Connor)" <humin29@huawei.com>]

在 2021/3/17 23:28, Ferruh Yigit 写道:
> On 3/17/2021 1:14 AM, Min Hu (Connor) wrote:
>>
>>
>> 在 2021/3/16 20:40, Ferruh Yigit 写道:
>>> On 3/12/2021 11:51 AM, Min Hu (Connor) wrote:
>>>> From: Chengwen Feng <fengchengwen@huawei.com>
>>>>
>>>> Currently, the driver support multiple IO burst function and auto
>>>> selection of the most appropriate function based on offload
>>>> configuration.
>>>>
>>>> Most applications such as l2fwd/l3fwd don't provide the means to
>>>> change offload configuration, so it will use the auto selection's io
>>>> burst function.
>>>>
>>>> This patch support runtime config to select io burst function, which
>>>> add two config: rx_func_hint and tx_func_hint, both could assign
>>>> vec/sve/simple/common.
>>>>
>>>> The driver will use the following rules to select io burst func:
>>>> a. if hint equal vec and meet the vec Rx/Tx usage condition then use
>>>> the neon function.
>>>> b. if hint equal sve and meet the sve Rx/Tx usage condition then use
>>>> the sve function.
>>>> c. if hint equal simple and meet the simple Rx/Tx usage condition then
>>>> use the simple function.
>>>> d. if hint equal common then use the common function.
>>>> e. if hint not set then:
>>>> e.1. if meet the vec Rx/Tx usage condition then use the neon function.
>>>> e.2. if meet the simple Rx/Tx usage condition then use the simple
>>>> function.
>>>> e.3. else use the common function.
>>>>
>>>> Note: the sve Rx/Tx usage condition based on the vec Rx/Tx usage
>>>> condition and runtime environment (which must support SVE).
>>>>
>>>> In the previous versions, driver will preferred use the sve function
>>>> when meet the sve Rx/Tx usage condition, but in this case driver could
>>>> get better performance if use the neon function.
>>>>
>>>> Signed-off-by: Chengwen Feng <fengchengwen@huawei.com>
>>>> Signed-off-by: Min Hu (Connor) <humin29@huawei.com>
>>>> ---
>>>>   doc/guides/nics/hns3.rst               | 20 +++++++++
>>>>   doc/guides/rel_notes/release_21_05.rst |  1 +
>>>>   drivers/net/hns3/hns3_ethdev.c         | 77 
>>>> ++++++++++++++++++++++++++++++++++
>>>>   drivers/net/hns3/hns3_ethdev.h         | 15 +++++++
>>>>   drivers/net/hns3/hns3_ethdev_vf.c      |  4 ++
>>>>   drivers/net/hns3/hns3_rxtx.c           | 54 +++++++++++++++++-------
>>>>   6 files changed, 157 insertions(+), 14 deletions(-)
>>>>
>>>> diff --git a/doc/guides/nics/hns3.rst b/doc/guides/nics/hns3.rst
>>>> index 84bd7a3..40d2e3b 100644
>>>> --- a/doc/guides/nics/hns3.rst
>>>> +++ b/doc/guides/nics/hns3.rst
>>>> @@ -46,6 +46,26 @@ Prerequisites
>>>>   - Follow the DPDK :ref:`Getting Started Guide for Linux 
>>>> <linux_gsg>` to setup the basic DPDK environment.
>>>> +Runtime Config Options
>>>> +----------------------
>>>> +
>>>> +- ``rx_func_hint`` (default ``none``)
>>>> +
>>>> +  Used to select Rx burst function, supported value are "vec", 
>>>> "sve", "simple", "common".
>>>> +  When equal "vec" and meet the vector Rx usage condition then use 
>>>> the neon Rx function.
>>>> +  When equal "sve" and meet the sve Rx usage condition then use the 
>>>> sve Rx function.
>>>> +  When equal "simple" and meet the simple Rx usage condition then 
>>>> use the simple Rx function.
>>>> +  When equal "common" then use the common Rx function.
>>>> +
>>>> +- ``tx_func_hint`` (default ``none``)
>>>> +
>>>> +  Used to select Tx burst function, supported value are "vec", 
>>>> "sve", "simple", "common".
>>>> +  When equal "vec" and meet the vector Tx usage condition then use 
>>>> the neon Tx function.
>>>> +  When equal "sve" and meet the sve Tx usage condition then use the 
>>>> sve Tx function.
>>>> +  When equal "simple" and meet the simple Tx usage condition then 
>>>> use the simple Tx function.
>>>> +  When equal "common" then use the common Tx function.
>>>> +
>>>
>>> I think 'vec' & 'sve' are more self explenatory, but can you please 
>>> describe what is 'common' and 'simple', and the difference of these two?
>> In the Rx direction, simple indicates that the Scalar algorithm 
>> obtained from rte_eth_rx_burst_mode_get, and common indicates that the 
>> Scalar Scattered algorithm obtained from rte_eth_rx_burst_mode_get.
>>
>> In the TX direction, simple indicates that the Scalar Simple algorithm 
>> in the rte_eth_tx_burst_mode_get, and common indicates that the Scalar 
>> algorithm obtained in the rte_eth_tx_burst_mode_get.
>>
> 
> Got it, can you please document what you described above in this document?
> 
done it, I have sent V5, please check it, thanks.
>> Later, we will send a patch to modify the names obtained in 
>> rte_eth_rx_burst_mode_get, that is, the original Scalar is renamed 
>> Scalar Simple and Scalar Scattered is renamed Scalar. The Rx and Tx 
>> are not in correspondence, which may leads to misunderstanding.
>>
>>>
>>> btw, since both 'neon' and 'sve' are vector implementations, what do 
>>> you think to have arguments as 'neon' & 'sve', instead of 'vec' & 'sve'?
>> 'vec' here means the default vector type in the current platform(In 
>> future, we will support NIC in different kinds of platform). when the 
>> DPDK run on different platform, the default vector will be different. 
>> For instance, now in ARM soc, 'vec' means 'neon', in X86 platform, 'vec'
>> means 'SSE/AVX' or others.
>>
> 
> I see, again can you document this above, in document for 'vec' it says 
> "use the neon", instead it can say something like "use default vector 
> implementation, 'neon' for Arm" ...
> 
done it, I have sent V5, please check it, thanks.
> Btw, I can see v4 sent, but there is no changelog, and documentation 
> seems same, what has changed there?
> 
I have added changelog, I have sent V5, please check it, thanks.
> .