On 22.5.2023. 22:17, Alexander Bluhm wrote:
> Hi,
>
> I noticed a missing checksum count in netstat tcp packets sent
> software-checksummed. Turns out that our syn cache does the checksum
> calculation by hand, instead of the established mechanism in ip
> output.
>
> Just set the flag M_TCP_CSUM_OUT and let in_proto_cksum_out() do
> the work later.
>
> While there remove redundant code. The unhandled af case is handled
> in the first switch statement of the function.
Hi,
from time to time when doing iperf from openbsd to linux,
"output TSO packets software chopped" counter is increasing when
starting iperf tests, but not while tests are running.
smc4# netstat -sp tcp | grep TSO
19 output TSO packets software chopped
66504137 output TSO packets hardware processed
752185165 output TSO packets generated
0 output TSO packets dropped
Because I played with MTU, I thought, it's could be some quirk with MTU
mismatch, TCP fragments or something like that, but that's not the case.
Software chopped counter is increasing even with align MTU
It's not that there's any problems with or without this diff, I'm always
getting 10Gbps per tcp flow with HW TSO, I just thought that this diff
would fix that but it didn't.
