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| author | Haiyang Zhang <haiyangz@microsoft.com> | 2023-10-11 23:30:44 +0300 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2023-10-17 00:55:32 +0300 |
| commit | 562b1fdf061bff9394ccd884456ed1173c224fdc (patch) | |
| tree | e56864865571c6600af484f5e701ba535e6b8f32 /Documentation/networking | |
| parent | 39d08b91646d83e87f7cbcd846b3ef33b1a53b79 (diff) | |
| download | linux-562b1fdf061bff9394ccd884456ed1173c224fdc.tar.xz | |
tcp: Set pingpong threshold via sysctl
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>
Diffstat (limited to 'Documentation/networking')
| -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 f7dfde3b09a9..e7ec9026e5db 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 ============= |