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How to disable TCP slow start in Linux?

I am looking for disable TCP slow start mechanism for high-speed network. Currently clients send 100MB flows to random servers with non-blocking 1Gbps link. In my math, the completion time of the flows is less than 1 second.

But the problem is that they cannot reach to a full link bandwidth. In other words, they are finished at slow start phase before getting a full link bandwidth.
Therefore, I want to increase TCP congestion window size to maximum.

Is there anyone who know how to change that value easily without modification the kernel?

like image 368
Junho Suh Avatar asked Jun 10 '13 00:06

Junho Suh


1 Answers

On Linux platforms the SSR setting can be checked and disabled via the following commands:

$> sysctl net.ipv4.tcp_slow_start_after_idle
$> sysctl -w net.ipv4.tcp_slow_start_after_idle=0

Slow start is also used after a connection has been idle, unless this behavior is disabled in

/proc/sys/net/ipv4/tcp_slow_start_after_idle.
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a.m. Avatar answered Sep 24 '22 06:09

a.m.