From: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx> Date: Wed, 11 Oct 2023 13:30:44 -0700 > TCP pingpong threshold is 1 by default. But some applications, like SQL DB > may prefer a higher pingpong threshold to activate delayed acks in quick > ack mode for better performance. > > The pingpong threshold and related code were changed to 3 in the year > 2019 in: > commit 4a41f453bedf ("tcp: change pingpong threshold to 3") > And reverted to 1 in the year 2022 in: > commit 4d8f24eeedc5 ("Revert "tcp: change pingpong threshold to 3"") > > There is no single value that fits all applications. > Add net.ipv4.tcp_pingpong_thresh sysctl tunable, so it can be tuned for > optimal performance based on the application needs. > > Signed-off-by: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx> Reviewed-by: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx> Thanks!