diff options
| author | Eric Dumazet <edumazet@google.com> | 2025-11-14 13:51:41 +0000 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2025-11-17 17:02:43 -0800 |
| commit | ca412f25d6b2c21f69a6cf12da062e0be4a5f45e (patch) | |
| tree | 9d12912cc1443071cfb1452571174019c505776f /Documentation/networking | |
| parent | 5860bb1ce0ddb9c5c964f7b46a8f0c4a48f919b1 (diff) | |
tcp: reduce tcp_comp_sack_slack_ns default value to 10 usec
net.ipv4.tcp_comp_sack_slack_ns current default value is too high.
When a flow has many drops (1 % or more), and small RTT, adding 100 usec
before sending SACK stalls the sender relying on getting SACK
fast enough to keep the pipe busy.
Decrease the default to 10 usec.
This is orthogonal to Congestion Control heuristics to determine
if drops are caused by congestion or not.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Link: https://patch.msgid.link/20251114135141.3810964-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'Documentation/networking')
| -rw-r--r-- | Documentation/networking/ip-sysctl.rst | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst index 2bae61be1859..f4ad739a6b53 100644 --- a/Documentation/networking/ip-sysctl.rst +++ b/Documentation/networking/ip-sysctl.rst @@ -875,8 +875,9 @@ tcp_comp_sack_slack_ns - LONG INTEGER timer used by SACK compression. This gives extra time for small RTT flows, and reduces system overhead by allowing opportunistic reduction of timer interrupts. + Too big values might reduce goodput. - Default : 100,000 ns (100 us) + Default : 10,000 ns (10 us) tcp_comp_sack_nr - INTEGER Max number of SACK that can be compressed. |