zoukankan      html  css  js  c++  java
  • TCP拥塞控制算法 — CUBIC的补丁(五)

    描述

    以下是提交者Sangtae Ha对这个patch的描述:

    make the delay threshold of HyStart less sensitive

    Make HyStart less sensitive to abrupt delay variations due to buffer bloat.

    代码

    --- a/net/ipv4/tcp_cubic.c
    +++ b/net/ipv4/tcp_cubic.c
    @@ -39,7 +39,7 @@
     
     /* Number of delay samples for detecting the increase of delay */
     #define HYSTART_MIN_SAMPLES	8
    -#define HYSTART_DELAY_MIN	(2U<<3)
    +#define HYSTART_DELAY_MIN	(4U<<3)
     #define HYSTART_DELAY_MAX	(16U<<3)
     #define HYSTART_DELAY_THRESH(x)	clamp(x, HYSTART_DELAY_MIN, HYSTART_DELAY_MAX)

    评价

    增大了Delay Increase的最小阈值,减小HyStart因为正常的时延抖动而过早退出的概率。

    我们知道目前的路由器缓存普遍偏大,这就意味着排队时延的抖动不可避免。

    之前Delay Increase的阈值:

    (1) delay_min < 32ms, threshold = 2ms

    (2) 32ms <= delay_min <= 256ms, threshold = delay_min/16 ms

    (3) delay_min > 256ms, threshold = 16ms

    现在Delay Increase的阈值:

    (1) delay_min < 64ms, threshold = 4ms

    (2) 64ms <= delay_min <= 256ms, threshold = delay_min/16 ms

    (3) delay_min > 256ms, threshold = 16ms

    Author

    zhangskd @ csdn blog

  • 相关阅读:
    填空:类型转换1
    :其他基本数据类型存储空间大小
    10:Hello, World!的大小
    09:整型与布尔型的转换
    08:打印字符
    07:打印ASCII码
    06:浮点数向零舍入
    05:填空:类型转换2
    04:填空:类型转换1
    03:其他基本数据类型存储空间大小
  • 原文地址:https://www.cnblogs.com/aiwz/p/6333349.html
Copyright © 2011-2022 走看看