Re: [PATCH mptcp-next] Squash to "selftests: mptcp: add MP_FAIL reset testcase" - cleanups

[Mat Martineau <mathew.j.martineau@linux.intel.com>]

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On Wed, 4 May 2022, Mat Martineau wrote:

> On Wed, 4 May 2022, Geliang Tang wrote:
>
>> Paolo Abeni <pabeni@redhat.com> 于2022年5月4日周三 21:04写道：
>>> 
>>> Hi Geliang,
>>> 
>>> On Wed, 2022-05-04 at 20:14 +0800, Geliang Tang wrote:
>>>> On Wed, May 04, 2022 at 07:44:24PM +0800, Geliang Tang wrote:
>>>>> Two small cleanups for MP_FAIL reset test case:
>>>>> 
>>>>> Reduce the test files size from 1024 to 128, to make the test faster.
>>>> 
>>>> The original commit log needs to update too:
>>>>
>>>>  1024KB -> 128KB
>>>> 
>>>> '''
>>>> Add the multiple subflows test case for MP_FAIL, to test the MP_FAIL
>>>> reset case. Use the test_linkfail value to make 128KB test files.
>>>> 
>>>> ...
>>>> ...
>>>> '''
>>>> 
>>>>> With Paolo's fix [2] for MP_FAIL test-case, the test becomes very slow.
>>>>> 
>>>>> Drop '+'s passed to chk_csum_nr, with Paolo's fix [1] for act_pedit, no
>>>>> extra checksum failures now, no need to add '+'s anymore.
>>>>> 
>>>>> Depends on Paolo's commits:
>>>>> [1] net/sched: act_pedit: really ensure the skb is writable
>>>>> [2] selftests: mptcp: fix MP_FAIL test-case
>>>>> 
>>>>> Signed-off-by: Geliang Tang <geliang.tang@suse.com>
>>> 
>>> I noticed the the time increase. Unfortunatelly, it may be necessary to
>>> be reliable in all environment, comprising the slowers one.
>>> 
>>> Mat (M.) was able to reproduce some failure with b/w == 10Mbps and size
>>> == 1M. I think/guess he could hit the same failure even with 1Mbps and
>>> size == 128K.
>>> 
>>> We need at least some additional testing for this one.
>> 
>> If so, let's continue to use 1024k test file sizes.
>> 
>
> It's reliable for me at 128k so far. I'm fine with squashing the patch as-is, 
> we can increase the file size if CI (or humans) complain.
>

It did fail after 193 iterations (kernel with debug config):

002 MP_FAIL MP_RST: 1 corrupted pkts     syn[ ok ] - synack[ ok ] - ack[ ok ]
                                          sum[ ok ] - csum  [ ok ]
                                          ftx[ ok ] - failrx[fail] got 0 MP_FAIL[s] RX expected 1

So 128k seems to be too small.

--
Mat Martineau
Intel