Re: Hit regression with TCP_TW REUSE/RECYCLE

From	Eric Dumazet <eric.dumazet@gmail.com>
Newsgroups	linux.kernel
Subject	Re: Hit regression with TCP_TW REUSE/RECYCLE
Date	2015-11-17 13:10 +0100
Message-ID	<qvNfb-4R6-3@gated-at.bofh.it> (permalink)
References	<quWXf-4WF-1@gated-at.bofh.it> <qvI5P-1mW-1@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Tue, 2015-11-17 at 14:35 +0800, Ethan Zhao wrote:
> Tested the same case with 4.4-RC1, it was fixed in 4.4-RC1.
> But don't know which commit fixed it.
> 
>  # echo 1024 65535 > /proc/sys/net/ipv4/ip_local_port_range
>  # cat /proc/sys/net/ipv4/ip_local_port_range
> 1024    65535
>  # echo 1 > /proc/sys/net/ipv4/tcp_tw_reuse
>  #  cat /proc/sys/net/ipv4/tcp_tw_reuse
> 1
>  # echo 1 > /proc/sys/net/ipv4/tcp_tw_recycle
>  #  cat /proc/sys/net/ipv4/tcp_tw_reuse
> 1
>  # ./accept -n 5 -r &
> [1] 11866
>  # port: 7954
> ninst: 5
> reuseport: 1
> 
>  # ./connect -i 127.0.0.1 -n 5 -d 10
> 78578.50
>  # uname -a
> Linux localhost.localdomain 4.4.0-rc1 #49 SMP Tue Nov 17 15:04:18 KST
> 2015 x86_64 x86_64 x86_64 GNU/Linux

Maybe run a reverse bisection ?

tcp_tw_reuse and tcp_tw_recycle both set to one have never been
supported in linux.

tcp_tw_recycle - BOOLEAN
        Enable fast recycling TIME-WAIT sockets. Default value is 0.
        It should not be changed without advice/request of technical
        experts.

tcp_tw_reuse - BOOLEAN
        Allow to reuse TIME-WAIT sockets for new connections when it is
        safe from protocol viewpoint. Default value is 0.
        It should not be changed without advice/request of technical
        experts.

Thanks.


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Thread

Re: Hit regression with TCP_TW REUSE/RECYCLE Ethan Zhao <ethan.kernel@gmail.com> - 2015-11-17 07:40 +0100
  Re: Hit regression with TCP_TW REUSE/RECYCLE Eric Dumazet <eric.dumazet@gmail.com> - 2015-11-17 13:10 +0100
    Re: Hit regression with TCP_TW REUSE/RECYCLE Ethan Zhao <ethan.kernel@gmail.com> - 2015-11-20 04:20 +0100

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