Re: [PATCH net-next 0/4] selftests/net: packetdrill: import multiple tests

[Paolo Abeni <pabeni@redhat.com>]

On 12/18/24 19:00, Jakub Kicinski wrote:
> On Tue, 17 Dec 2024 18:51:57 +0000 Soham Chakradeo wrote:
>> Import tests for the following features (folder names in brackets):
>> ECN (ecn) : RFC 3168
>> Close (close) : RFC 9293
>> TCP_INFO (tcp_info) : RFC 9293
>> Fast recovery (fast_recovery) : RFC 5681
>> Timestamping (timestamping) : RFC 1323
>> Nagle (nagle) : RFC 896
>> Selective Acknowledgments (sack) : RFC 2018
>> Recent Timestamp (ts_recent) : RFC 1323
>> Send file (sendfile)
>> Syscall bad arg (syscall_bad_arg)
>> Validate (validate)
>> Blocking (blocking)
>> Splice (splice)
>> End of record (eor)
>> Limited transmit (limited_transmit)
> 
> Excellent, thanks for adding all these! I will merge the patches
> momentarily but I do see a number of flakes on our VMs with debug
> configs enabled:
> https://netdev.bots.linux.dev/flakes.html?min-flip=0&tn-needle=packetdrill-dbg
> 
> In the 7 runs so far we got 2 flakes on:
> 
>  tcp-timestamping-client-only-last-byte-pkt

Quickly skimming over this one, it looks like it does not account for
the increased default 'tolerance_us'. Kernel packetdrill set it by
default to 14K (instead of 10K IIRC).

I guess this statement:

// SCM_TSTAMP_SCHED for the last byte should be received almost immediately
// once 10001 is acked at t=20ms.

the the follow-up check should be updated accordingly. In the failures
observed so far the max timestamp is > 35ms.

Cheers,

Paolo