Re: [PATCH net-next v2] selftests: drv-net: add BIG TCP test cases

[Jakub Kicinski]

On Fri, 11 Sep 2026 22:03:27 -0700 Narcisa Vasile wrote:
> Add four new test cases that validate coalescing
> under increased size limits (BIG TCP):
> 
> big_tcp_data_same
>   - validates that equal-sized segments coalesce past
>    the legacy IP_MAXPACKET limit.
> big_tcp_data_lrg_sml
>   - validates that a smaller final segment coalesces into the
>     previous chain of large-sized segments while crossing the
>     IP_MAXPACKET limit.
> big_tcp_tcp_seq
>   - validates that a packet with a wrong sequence number doesn't
>     coalesce. The test uses a sequence number for which the low 16 bits
>     correspond to the correct sequence number to validate against
>     truncation bugs, since total aggregate length crosses over the
>     legacy size limit for BIG TCP.
> big_tcp_large_max
>   - validates that coalescing stops at the configured BIG TCP limit.
 
Still failing:

https://netdev-ctrl.bots.linux.dev/logs/vmksft/net-drv-dbg/results/819882/3-gro-sw-py/stdout

https://netdev-ctrl.bots.linux.dev/logs/vmksft/net-drv-dbg/results/819882/3-gro-sw-py-retry/stdout

Grep gro_lib.py for KSFT_MACHINE_SLOW
Then the 15x increase is probably unnecessary/too high as well, since
we GRO 64k 128k shouldn't need more than 2x ?