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authorHaiyang Zhang <haiyangz@microsoft.com>2023-10-11 13:30:44 -0700
committerJakub Kicinski <kuba@kernel.org>2023-10-16 14:55:32 -0700
commit562b1fdf061bff9394ccd884456ed1173c224fdc (patch)
treee56864865571c6600af484f5e701ba535e6b8f32 /net/ipv4/tcp_output.c
parent39d08b91646d83e87f7cbcd846b3ef33b1a53b79 (diff)
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 'net/ipv4/tcp_output.c')
-rw-r--r--net/ipv4/tcp_output.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index d5961a82a9e8..8e6ebf35ed58 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -170,10 +170,10 @@ static void tcp_event_data_sent(struct tcp_sock *tp,
tp->lsndtime = now;
/* If it is a reply for ato after last received
- * packet, enter pingpong mode.
+ * packet, increase pingpong count.
*/
if ((u32)(now - icsk->icsk_ack.lrcvtime) < icsk->icsk_ack.ato)
- inet_csk_enter_pingpong_mode(sk);
+ inet_csk_inc_pingpong_cnt(sk);
}
/* Account for an ACK we sent. */