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Miller" , Jakub Kicinski , Simon Horman , Neal Cardwell , Willem de Bruijn , Kuniyuki Iwashima , netdev@vger.kernel.org, eric.dumazet@gmail.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Tue, Oct 14, 2025 at 1:22=E2=80=AFAM Paolo Abeni wro= te: > > On 10/13/25 4:59 PM, Eric Dumazet wrote: > > Some applications uses TCP_TX_DELAY socket option after TCP flow > > is established. > > > > Some metrics need to be updated, otherwise TCP might take time to > > adapt to the new (emulated) RTT. > > > > This patch adjusts tp->srtt_us, tp->rtt_min, icsk_rto > > and sk->sk_pacing_rate. > > > > This is best effort, and for instance icsk_rto is reset > > without taking backoff into account. > > > > Signed-off-by: Eric Dumazet > > The CI is consistently reporting pktdrill failures on top of this patch: > > # selftests: net/packetdrill: tcp_user_timeout_user-timeout-probe.pkt > # TAP version 13 > # 1..2 > # tcp_user_timeout_user-timeout-probe.pkt:35: error in Python code > # Traceback (most recent call last): > # File "/tmp/code_T7S7S4", line 202, in > # assert tcpi_probes =3D=3D 6, tcpi_probes; \ > # AssertionError: 0 > # tcp_user_timeout_user-timeout-probe.pkt: error executing code: > 'python3' returned non-zero status 1 > > To be accurate, the patches batch under tests also includes: > > https://patchwork.kernel.org/project/netdevbpf/list/?series=3D1010780 > > but the latter looks even more unlikely to cause the reported issues?!? > > Tentatively setting this patch to changes request, to for CI's sake. I will take a look, thanks. I ran our ~2000 packetdrill tests for the tcp_tso_should_defer() fix, but had no coverage yet for TCP_TX_DELAY, and started adding packetdrill tests for that.