This is a note to let you know that I've just added the patch titled selftests: net: let big_tcp test cope with slow env to the 6.6-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: selftests-net-let-big_tcp-test-cope-with-slow-env.patch and it can be found in the queue-6.6 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit d9c2b0e33d3d1e2e53d4d1427c706022470fe090 Author: Paolo Abeni <pabeni@xxxxxxxxxx> Date: Fri Feb 2 17:06:59 2024 +0100 selftests: net: let big_tcp test cope with slow env [ Upstream commit a19747c3b9bf6476cc36d0a3a5ef0ff92999169e ] In very slow environments, most big TCP cases including segmentation and reassembly of big TCP packets have a good chance to fail: by default the TCP client uses write size well below 64K. If the host is low enough autocorking is unable to build real big TCP packets. Address the issue using much larger write operations. Note that is hard to observe the issue without an extremely slow and/or overloaded environment; reduce the TCP transfer time to allow for much easier/faster reproducibility. Fixes: 6bb382bcf742 ("selftests: add a selftest for big tcp") Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx> Reviewed-by: Eric Dumazet <edumazet@xxxxxxxxxx> Acked-by: Xin Long <lucien.xin@xxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/tools/testing/selftests/net/big_tcp.sh b/tools/testing/selftests/net/big_tcp.sh index cde9a91c4797..2db9d15cd45f 100755 --- a/tools/testing/selftests/net/big_tcp.sh +++ b/tools/testing/selftests/net/big_tcp.sh @@ -122,7 +122,9 @@ do_netperf() { local netns=$1 [ "$NF" = "6" ] && serip=$SERVER_IP6 - ip net exec $netns netperf -$NF -t TCP_STREAM -H $serip 2>&1 >/dev/null + + # use large write to be sure to generate big tcp packets + ip net exec $netns netperf -$NF -t TCP_STREAM -l 1 -H $serip -- -m 262144 2>&1 >/dev/null } do_test() {