networking network_error ai_generated partial

TCP：由于在10.0.0.1:443上过度重传，SACK已被禁用

TCP: SACK has been disabled due to excessive retransmissions on 10.0.0.1:443

ID: networking/tcp-sack-perf-downshift

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78%修复率
85%置信度
1证据数
2024-03-15首次发现

版本兼容性

版本状态引入弃用备注
Linux kernel 5.15 active — — —
Linux kernel 6.1 active — — —
Linux kernel 6.8 active — — —

根因分析

当TCP连接经历高重传率时，内核会自动禁用TCP选择性确认（SACK）功能，这通常是由于数据包损坏或中间设备丢弃/损坏SACK选项所致。

English

The TCP Selective Acknowledgment (SACK) feature is automatically disabled by the kernel when the TCP connection experiences a high rate of retransmissions, often due to packet corruption or a misbehaving intermediate device that drops or corrupts SACK options.

generic

官方文档

https://www.kernel.org/doc/html/latest/networking/ip-sysctl.html

解决方案

  1. ethtool -S eth0 | grep -i crc
  2. ip route change 10.0.0.0/24 dev eth0 proto kernel scope link src 10.0.0.1 metric 100 tcp_sack 1

无效尝试

常见但无效的做法:

  1. Setting net.ipv4.tcp_sack=0 to prevent the error from appearing. 90% 失败

    This disables SACK entirely, which reduces throughput for all connections, and does not address the root cause (e.g., packet corruption or middlebox interference).

  2. Increasing tcp_rmem and tcp_wmem to accommodate retransmissions. 70% 失败

    Larger buffers may hide the symptom temporarily but do not fix the underlying issue causing retransmissions (e.g., faulty NIC or cable).