On 2020/9/17 19:16, Ferruh Yigit wrote:
> On 9/17/2020 8:10 AM, Chengchang Tang wrote:
>>
>>
>> On 2020/9/15 0:23, Ferruh Yigit wrote:
>>> On 8/20/2020 2:42 AM, Wei Hu (Xavier) wrote:
>>>> From: Chengchang Tang <tangchengch...@huawei.com>
>>>>
>>>> In txonly forward mode, the packet header is fixed by the initial
>>>> setting, including the packet length and checksum. So when the packets
>>>> varies, this may cause a packet header error. Currently, there are two
>>>> methods in txonly mode to randomly change the packets.
>>>> 1. Set txsplit random and txpkts (x[,y]*), the number of segments
>>>> each packets will be a random value between 1 and total number of
>>>> segments determined by txpkts settings.
>>>> The step as follows:
>>>> a) ./testpmd -w xxx -l xx -n 4 -- -i --rxd xxxx --txd xxxx
>>>> b) set fwd txonly
>>>> c) set txsplit rand
>>>> d) set txpkts 2048,2048,2048,2048
>>>> e) start
>>>> The nb_segs of the packets sent by testpmd will be 1~4. The real packet
>>>> length will be 2048, 4096, 6144 and 8192. But in fact the packet length
>>>> in ip header and udp header will be fixed by 8178 and 8158.
>>>
>>> Although I confirm the patch fixes the ip & udp header packet size for
>>> "txsplit=rand" config,
>>> I am always getting actual packet size wrong, independent from
>>> 'txsplit', and it is always first segment size. Am I doing something wrong?
>>
>> Yes, I miss it. If the txsplit is not set and the txpkts is set, the txonly
>> fwd engine will only send single segment packets, and there will be a payload
>> error for the data_len will be refreshed by the sum of the segment size.
>>
>
> I am getting the size error when 'txsplit' is 'on' or 'rand'. In that case
> packet header are correct (after your patch) but wireshark complains the size
> of the packet on wire is different than the values in headers. And the size
> of the actual packet is reported by wireshark as the size of the first
> segment.
Maybe it should be configured with multi_segs offload. If the 'txsplit' is 'on'
or 'rand',
the txonly engine will send a multi segments packets. I tested it on hns3 PMD,
which
support a multi_segs by default configuration. So, I miss to add these
information to
the commit log. For some PMDs, the multi_segs is not support as default.
>> May be the data_len should be the first segment size if the txsplit is not
>> set?
>> I will fix it in the next version.
>>>
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>
>
> .
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