We see quite a few flakes during the TSO test against virtualized devices in NIPA. There's often 10-30 retransmissions during the test. Sometimes as many as 100. Set the retransmission threshold at 1/4th of the wire frame target.

Signed-off-by: Jakub Kicinski kuba@kernel.org --- CC: shuah@kernel.org CC: willemb@google.com CC: daniel.zahka@gmail.com CC: linux-kselftest@vger.kernel.org --- tools/testing/selftests/drivers/net/hw/tso.py | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/tools/testing/selftests/drivers/net/hw/tso.py b/tools/testing/selftests/drivers/net/hw/tso.py index c13dd5efa27a..0998e68ebaf0 100755 --- a/tools/testing/selftests/drivers/net/hw/tso.py +++ b/tools/testing/selftests/drivers/net/hw/tso.py @@ -60,16 +60,17 @@ from lib.py import bkg, cmd, defer, ethtool, ip, rand_port, wait_port_listen sock_wait_drain(sock) qstat_new = cfg.netnl.qstats_get({"ifindex": cfg.ifindex}, dump=True)[0]

- # No math behind the 10 here, but try to catch cases where - # TCP falls back to non-LSO. - ksft_lt(tcp_sock_get_retrans(sock), 10) - sock.close() - # Check that at least 90% of the data was sent as LSO packets. # System noise may cause false negatives. Also header overheads # will add up to 5% of extra packes... The check is best effort. total_lso_wire = len(buf) * 0.90 // cfg.dev["mtu"] total_lso_super = len(buf) * 0.90 // cfg.dev["tso_max_size"] + + # Make sure we have order of magnitude more LSO packets than + # retransmits, in case TCP retransmitted all the LSO packets. + ksft_lt(tcp_sock_get_retrans(sock), total_lso_wire / 4) + sock.close() + if should_lso: if cfg.have_stat_super_count: ksft_ge(qstat_new['tx-hw-gso-packets'] -