diff options
| author | Haiyang Zhang | 2023-10-11 13:30:44 -0700 |
|---|---|---|
| committer | Sasha Levin | 2026-03-04 07:20:22 -0500 |
| commit | 4ec8a98b3dc3cdb0344bcda12847597a141d61d6 (patch) | |
| tree | edaf096147710198e20c142017204cd1d5cd466b /Documentation | |
| parent | b4d5e97679bc786687879710dc2de280c70ca889 (diff) | |
tcp: Set pingpong threshold via sysctl
[ Upstream commit 562b1fdf061bff9394ccd884456ed1173c224fdc ]
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@microsoft.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/1697056244-21888-1-git-send-email-haiyangz@microsoft.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Stable-dep-of: 87b08913a9ae ("inet: move icmp_global_{credit,stamp} to a separate cache line")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/networking/ip-sysctl.rst | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst index 5bfa1837968c..531a070df2a6 100644 --- a/Documentation/networking/ip-sysctl.rst +++ b/Documentation/networking/ip-sysctl.rst @@ -1183,6 +1183,19 @@ tcp_plb_cong_thresh - INTEGER Default: 128 +tcp_pingpong_thresh - INTEGER + The number of estimated data replies sent for estimated incoming data + requests that must happen before TCP considers that a connection is a + "ping-pong" (request-response) connection for which delayed + acknowledgments can provide benefits. + + This threshold is 1 by default, but some applications may need a higher + threshold for optimal performance. + + Possible Values: 1 - 255 + + Default: 1 + UDP variables ============= |